[top]
000
FXUS62 KCAE 242048
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
448 PM EDT FRI MAY 24 2013
.SYNOPSIS...
COOL HIGH PRESSURE WILL SETTLE OVER THE REGION FOR THE
WEEKEND...BRINGING BELOW NORMAL TEMPERATURES AND DRY WEATHER.
&&
.NEAR TERM /TONIGHT/...
HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION FROM THE
NORTHWEST WITH WEAK COLD ADVECTION CONTINUING THROUGH TONIGHT.
WINDS WILL RELAX WITH SUNSET AND THE LOSS OF GOOD MIXING. PRECIPITABLE
WATER VALUES WILL FALL BELOW A HALF INCH OVERNIGHT AND DEWPOINTS
WILL FALL INTO THE 40S...LEADING TO LOW FOG POTENTIAL.
NOT EXACTLY AN IDEAL RADIATIONAL COOLING SCENARIO TONIGHT ALTHOUGH
WINDS ARE LIKELY TO FALL TO NEAR CALM DURING THE PREDAWN HOURS ON
SATURDAY WHICH COULD ALLOW SOME OF THE OUTLYING AREAS TO DROP
SEVERAL DEGREES JUST BEFORE SUNRISE. WELL BELOW NORMAL
TEMPERATURES EXPECTED WITH POSSIBLE RECORD LOWS BEING REACHED IF
WINDS GO CALM EARLIER THAN EXPECTED AND DEWPOINTS DROP LOWER THAN
FORECAST. THINK LOWS WILL REMAIN A DEGREE OR TWO ABOVE RECORD
VALUES THOUGH.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
MODELS IN GOOD AGREEMENT SATURDAY THROUGH SUNDAY NIGHT. SHORT
WAVE EXITS TO THE EAST SATURDAY AS COOL HIGH PRESSURE BUILDS
ACROSS THE REGION THROUGH SATURDAY NIGHT. AIRMASS BEGINS TO MODIFY
BY SUNDAY AS OLD FRONTAL BOUNDARY TO THE SOUTH RETURNS NORTHWARD
AS A WARM FRONT. MOSTLY CLEAR SATURDAY BUT MORE CLOUDS BY SUNDAY
BUT NO RAIN AS ATMOSPHERE IS STILL DRY BOTH SUNDAY AND SUNDAY
NIGHT. COOL SATURDAY WITH HIGHS IN THE UPPER 70S...INCREASE TO THE
LOWER 80S BY SUNDAY. STILL COOL SATURDAY NIGHT BUT NOT AS COOL AS
FRIDAY NIGHT WITH LOWS IN THE UPPER 40S TO LOWER 50S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT SHOWING UPPER RIDGE
OVER THE MISSISSIPPI VALLEY MONDAY BUILDING EASTWARD ACROSS THE
REGION THROUGH THURSDAY. THE RIDGE BEGINS TO MOVE MORE TOWARD THE
EAST COAST FRIDAY. ALSO...A WARM FRONTAL BOUNDARY ACROSS THE
FORECAST AREA MONDAY LIFTS TO THE NORTHEAST AND AWAY FROM THE AREA
TUESDAY THROUGH FRIDAY. THIS UPPER RIDGE IS EXPECTED TO HOLD ANY
FRONTS WELL TO THE NORTH AND WEST DURING THE EXTENDED PERIOD.
SOUTH TO SOUTHWEST LOW LEVEL WIND FLOW WILL BRING MORE WARM
UNSTABLE AIR TO THE REGION AND THE ATMOSPHERE WILL BECOME
CONDITIONALLY UNSTABLE. STILL DRY MONDAY THOUGH BUT INCLUDED
DIURNAL CONVECTIVE ACTIVITY TUESDAY THROUGH THURSDAY. UPPER RIDGE
PRETTY STRONG AND JUST ABOUT RIGHT OVER THE AREA FRIDAY...SO LEFT
DRY FOR FRIDAY AS WELL. HIGHS IN THE MID 80S MONDAY AND TUESDAY
AND THE MID TO UPPER 80S WEDNESDAY THROUGH FRIDAY. OVERNIGHT LOWS
MAINLY IN THE LOWER 60S.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
NORTHWESTERLY WINDS 10-20 MPH WITH GUSTS TO 25 MPH THROUGH THE
EARLY EVENING. WINDS WILL WEAKEN BY SUNSET...REMAINING NORTHERLY.
CLEAR SKIES WITH NO FOG EXPECTED DUE TO DRY AIRMASS BUILDING INTO
THE REGION. NORTHERLY WINDS PICK UP TO AROUND 5-10 MPH AFTER 14Z
SATURDAY.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES WILL OCCUR TONIGHT WITH LOWS IN
THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW FOR MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW FOR MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
[top]
000
FXUS62 KGSP 242030
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
430 PM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL MOVE OFF THE ATLANTIC COAST TONIGHT AND
SATURDAY WHILE SURFACE HIGH PRESSURE CONTINUES THE COOLER THAN
NORMAL TEMPERATURES THIS WEEKEND. EXPECT AFTERNOON SHOWERS AND
THUNDERSTORMS NEXT WEEK...MAINLY OVER THE MOUNTAINS. A RATHER STRONG
UPPER RIDGE WILL BRING VERY WARM TEMPERATURES FOR THE SECOND HALF
OF THE WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
415 PM UPDATE...NO CHANGES TO FCST OTHER THAN TO TOUCH UP TEMP/DEWPT
TRENDS PER OBS. WITH WINDS RELAXING A TAD OVER THE NEXT HOUR IN
DIMINISHING PRESSURE GRADIENT...THERE MAY BE TIME FOR SUNSHINE TO
WARM TEMPS ANOTHER DEGREE OR SO.
THIS AFTERNOON...GUSTY NW WINDS WILL CONTINUE THROUGH SUNSET WITH A
FEW CLOUDS...OTHERWISE COOL AND DRY LIKE LATE APRIL.
FOR TONIGHT...AN UPPER TROF AXIS WILL SWING OFF THE EAST COAST
LEAVING BEHIND A DEEP NW FLOW THAT WILL BRING DOWN HIGH PRESSURE AND
COOL TEMPS...MORE THAN TEN DEGREES BELOW NORMAL. THE WIND SHOULD
DIMINISH SIGNIFICANTLY BY EARLY SATURDAY MORNING. THIS COULD BE
ENOUGH TO ALLOW FOR PATCHY FROST TO DEVELOP IN SOME OF THE SHELTERED
MOUNTAIN VALLEYS...PARTICULARLY THE LITTLE TN RIVER VALLEY. THE AREA
IMPACTED DOES NOT LOOK LARGE ENOUGH FOR A FROST ADVISORY SO THE
MENTION WILL REMAIN RELEGATED TO THE HWO.
SATURDAY IS SHAPING UP TO BE A BRIGHT...SUNNY...COOL...AND DRY DAY
WITH A LIGHT BREEZE...COURTESY OF SURFACE HIGH PRESSURE RIDGING DOWN
FROM THE GREAT LAKES. CHAMBER OF COMMERCE WEATHER FOR THE FIRST PART
OF MEMORIAL DAY WEEKEND. OPEN UP THE WINDOWS AND ENJOY IT NOW
BECAUSE IT WILL NOT LAST. TEMPS WERE KEPT CLOSE TO A GUIDANCE
BLEND...WHICH IS A COMFORTABLE FIVE DEGREES OR SO BELOW NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM FRIDAY...NW FLOW ALOFT WILL CONTINUE THROUGH SUNDAY AS
AN INTENSE UPPER LOW MOVES THROUGH NEW ENGLAND. THE FLOW WILL
DE-AMPLIFY ON MONDAY WITH BUILDING HEIGHTS AS THE LOW MOVES OUT THE
PICTURE. AT THE SURFACE...HIGH PRESSURE WILL RIDGE SOUTH FROM THE
SOUTHERN GREAT LAKES WITH A WEAK BACKDOOR FRONT MOVING THROUGH THE
AREA ON SUNDAY. THIS FRONT WILL MOVE NORTH AS A WARM FRONT ON
MONDAY. A MORE DOMINATE HIGH IS FORECAST TO DEVELOP OFF THE SE COAST
ON MONDAY.
A SERIES OF IMPULSES EMBEDDED IN THE NW FLOW ARE FORECAST TO MOVE
ACROSS THE AREA SUNDAY AND MONDAY. THE AIRMASS OVER THE REGION WILL
BE QUITE DRY IN THE LOWER LEVELS INITIALLY WITH DEWPOINTS IN THE 30S
AND 40S ON SUNDAY. HENCE...THE LACK OF SIGNIFICANT QPF RESPONSE IN
THE MODEL FORECASTS FOR SUN/SUN NIGHT IS NOT SURPRISING. WOULD EXPECT
THAT ANY PRECIP THAT FALLS SUNDAY AND SUNDAY NIGHT WILL BE MAINLY
VIRGA OR PERHAPS SOME SPRINKLES IN THE MOUNTAINS. MONDAY IS A
SLIGHTLY DIFFERENT STORY AS LOW LEVEL MOISTURE IMPROVES WITH
DEWPOINTS RISING INTO THE 50S AS THE WARM FRONT LIFTS NE.
THEREFORE...WOULD EXPECT SOME SCATTERED SHOWERS DEVELOPING IN THE
MOUNTAINS IN THE MORNING...WITH SCATTERED SHOWERS AND PERHAPS EVEN
SOME THUNDERSTORMS IN THE AFTERNOON....MAINLY OVER THE MOUNTAINS AND
THE NC FOOTHILLS/PIEDMONT.
TEMPERATURES WILL BE BELOW AVERAGE SAT NIGHT AND SUNDAY...WITH
MODERATING TEMPS ON MONDAY APPROACHING SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 150 PM FRIDAY...STARTING AT 00Z TUESDAY ALL MODELS SHOW SOME
MID LEVEL MOISTURE BETWEEN THE DEPARTING UPPER TROUGH WITH AXIS JUST
OFF THE NEW ENGLAND COAST AND THE EXPANDING UPPER RIDGE WITH AXIS
OVER EAST TEXAS. THIS LINEAR AREA OF MOISTURE EXTENDS FROM KY TO NC
MONDAY NIGHT THEN SHIFTS EAST AS RIDGE BUILDS FROM SW. SOUTHWESTERLY
LOW LEVEL FLOW WILL BRING WARMER AIR INTO THE REGION AS TEMPERATURES
WILL BE A LITTLE ABOVE NORMAL TUESDAY AND WEDNESDAY AND THEN TWO
CATEGORIES ABOVE NORMAL FOR HIGHS THURSDAY AND FRIDAY. INSTABILITY
WILL SUPPORT PM SHOWERS AND STORMS BUT FAVORING DIFFERENTIAL HEATING
OF THE MOUNTAINS. CAPE VALUES ARE MOST UNSTABLE ON ECMWF WITH 1000
TO 2000 VALUES EACH AFTERNOON. GFS IS MORE REASONABLE WITH 800 TO
1200 TUES...DROPPING TO LESS THAN 1000 FOR THE REST OF THE WEEK WITH
HIGHEST VALUES NORTH OF CLT TOWARD VA. MODELS HAVE CENTER OF 500MB
RIDGE OVER WESTERN NC THURSDAY. SEEMS MORE STABLE ON THURSDAY AND
EVEN MORE STABLE FRIDAY WITH DRIER LOW TO MID LEVEL. UPPER RIDGE
BEGINS TO MOVE OFF THE EAST COAST GOING INTO NEXT WEEKEND.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
21Z KCLT UPDATE...FCST ON TRACK THOUGH WINDS HAVE COME AROUND TO THE
NORTH A BIT FASTER THAN ANTICIPATED...SO WILL VEER WINDS SLIGHTLY IN
TAF. PRESSURE GRADIENT WILL CONTINUE TO WEAKEN WITH THE STRONGEST
GUSTS LIKELY BEHIND US ALREADY...BUT WILL KEEP GUST MENTION THRU
SUNSET AS IN PREV PACKAGE.
AT KCLT AND ELSEWHERE...VFR THROUGH THE PERIOD. A FEW STRATOCU WITH
BASES AT 050 TO 060 THROUGH SUNSET...THEN CLEAR AFTER 01Z. WIND WILL
REMAIN GUSTY FROM THE NW THROUGH SUNSET BUT WILL QUICKLY DIMINISH
AFTER THAT AS THE CENTER OF THE HIGH BUILDS IN. MOST PLACES WILL GO
LIGHT AND VARIABLE EARLY SATURDAY MORNING AND STAY THAT WAY THROUGH
THE REST OF THE TAF PERIOD...THE EXCEPTION BEING KAVL WHERE A NW
UPVALLEY WIND WILL BE MAINTAINED. COULD BE SOME FOG OR FROST IN THE
LITTLE TN RIVER VALLEY AROUND DAYBREAK SATURDAY...BUT NOT AROUND
KAVL.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED. A
RETURN TO DIURNAL THUNDERSTORMS IS EXPECTED FOR MONDAY THROUGH
WEDNESDAY WITH ASSOCIATED RESTRICTIONS IN THE VICINITY OF STORMS.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA THIS AFTERNOON. AFTERNOON MINIMUM RELATIVE
HUMIDITY VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...PM/WIMBERLEY
SHORT TERM...LG
LONG TERM...DEO
AVIATION...PM/WIMBERLEY
FIRE WEATHER...LG
[top]
000
FXUS62 KCHS 242014
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
414 PM EDT FRI MAY 24 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION THIS WEEKEND AND REMAIN
THE DOMINANT WEATHER FEATURE THROUGH LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
TONIGHT...THE SHARP UPPER TROUGH OVER THE MID-ATLANTIC WILL
TRANSITION TO A CLOSED LOW AS THE SURFACE HIGH CONTINUES TO BUILD
IN FROM THE NORTHWEST. A MUCH DRIER AND COOLER AIRMASS WILL FILTER
IN THROUGH THE OVERNIGHT...RESULTING IN SIGNIFICANTLY COOLER TEMPS.
IN FACT...LOWS WILL BOTTOM OUT IN THE UPPER 40S IN SOME LOCATIONS
INLAND. THESE MIN TEMPS WILL BE NEARLY 15 DEGREES BELOW CLIMO FOR
LATE MAY...AND WILL APPROACH A RECORD LOW FOR THE DOWNTOWN
CHARLESTON SITE. PLEASE SEE THE CLIMATE SECTION BELOW.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
A DEEP UPPER TROUGH OVER NEW ENGLAND AND AN UPPER RIDGE OVER THE
CENTRAL PART OF THE COUNTRY WILL PREVAIL THROUGH THE SUNDAY...THEN
WEAK UPPER RIDGING BUILDS OVER THE SOUTHEAST BY MONDAY. AT THE
SURFACE...HIGH PRESSURE WILL BE CENTERED OVER AND NORTH OF THE
REGION ON SATURDAY...THEN SHIFT EAST AND SLIGHTLY SOUTHEAST OF THE
AREA BY SUNDAY AND MONDAY. LIGHT NORTHERLY FLOW BECOMING ONSHORE
NEAR THE COAST FOR SATURDAY WITH HIGHS IN THE UPPER 70S TO AROUND
80...ABOUT 3-5 DEGS BELOW NORMAL. A WEAK FRONT AND MOISTURE
BAND MOVES INTO THE NORTHERN AREA LATER SATURDAY NIGHT AND
SUNDAY...BUT NO PRECIP IS EXPECTED THROUGH SUNDAY. ANOTHER COOL
NIGHT IN THE LOWER TO MID 50S MOST AREAS...CLOSE TO 10 DEGS BELOW
NORMAL FOR SATURDAY NIGHT. HIGH TEMPERATURES BACK CLOSER TO NORMAL BY
SUNDAY IN THE LOWER TO MID 80S...EXCEPT MID TO UPPER 70S NEAR THE
COAST DUE TO AN AFTERNOON SEA BREEZE/ONSHORE FLOW. PARTLY CLOUDY
SUNDAY NIGHT WITH SLIGHTLY WARMER TEMPS...BUT SILL COOLER THAN
NORMAL IN THE MID TO UPPER 50S. BY MONDAY...PARTLY CLOUDY SKIES AS
SOME LOW LEVEL MOISTURE TRIES TO RETURN WITH SSE LOW LEVEL FLOW.
TEMPS BACK IN THE LOWER TO MID 80S. MODELS ARE INDICATING SOME VERY
ISOLATED SHOWERS/TSTMS BY AFTERNOON OVER THE INTERIOR TRI-COUNTY
REGION...BUT HAVE NOT ADDED ANY PRECIP MENTION AT THIS TIME.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
DECENT MODEL AGREEMENT THIS PERIOD WITH ABOVE AVERAGE FORECAST
CONFIDENCE. UPPER HIGH PRESSURE SHOULD BUILD ACROSS THE REGION
TOWARD THE MIDDLE OF NEXT WEEK LEADING TO WARMING TEMPERATURES AND
SLOWLY INCREASING LOW-LEVEL MOISTURE. RAIN CHANCES WILL REMAIN LOW
GIVEN THE LACK OF DEEP MOISTURE AND FORCING...MAINLY CONFINED TO
INLAND AREAS DURING AFTERNOON PEAK HEATING AS THE SEA BREEZE PUSHES
INLAND.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH 18Z SATURDAY. GUSTY NW WINDS
WILL DIMINISH THIS EVENING WITH THE LOSS OF HEATING...AND THEN
WINDS WILL VEER AROUND TO MORE NORTHERLY OVERNIGHT.
EXTENDED AVIATION...VFR EXPECTED TO PREVAIL THROUGH EARLY TO MID
NEXT WEEK.
&&
.MARINE...
TONIGHT...AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST....A
TIGHTENING PRESSURE GRADIENT WILL RESULT IN A SURGE OF N/NE WINDS.
IN FACT...WITH WATER TEMPS IN THE MID 70S AND MUCH COOLER AIR
FILTERING IN GOOD MIXING CONDITIONS WILL BE IN PLACE. MODEL DATA
SUPPORTS A SEVERAL HOUR PERIOD OF LOW-END SMALL CRAFT ADVISORY
CONDITIONS ACROSS ALL WATERS. THE MAIN PARAMETER WILL BE WINDS
GUSTING TO 25 KTS...WITH 6 FT SEAS EXPECTED OUT NEAR 60 NM OVER
THE OUTER GA WATERS. THESE CONDITIONS WILL PERSIST THROUGH THE
OVERNIGHT PERIOD.
NNE WINDS SATURDAY MORNING AT 15 TO 20 KTS WILL DECREASE BY
AFTERNOON AS HIGH PRESSURE SETTLES OVER THE REGION. WINDS EXPECTED
TO BE LIGHT ENOUGH BY AFTERNOON TO BECOME ONSHORE NEAR THE COAST.
LIGHT WINDS OF 10-15 KTS SHOULD BECOME ONSHORE NEAR THE COAST AGAIN
SUNDAY. HIGH PRESSURE WILL REMAIN GENERALLY OVER THE REGION THROUGH
MID WEEK WITH SSE PREVAILING WINDS AND NO HIGHLIGHTS EXPECTED.
RIP CURRENTS...EXPECT A MODERATE RISK TO CONTINUE SATURDAY DUE TO
2-3 FOOT 8-9 SEC SWELLS AND NEW MOON. WOULD NOT BE SURPRISED IF
MODERATE RISK CONDITIONS CONTINUE THROUGH THE WEEKEND.
&&
.TIDES/COASTAL FLOODING...
CURRENT INDICATIONS FOR THIS EVENINGS HIGH TIDE INDICATE THAT WE
WILL FALL JUST SHORT OF COASTAL FLOOD ADVISORY CRITERIA AS WINDS
HAVE BEEN OFFSHORE THROUGH MUCH OF THE DAY. THEREFORE WE HAVE
OPTED TO NOT ISSUE AN ADVISORY WITH THIS PACKAGE...THOUGH WE WILL
CONTINUE TO MONITOR TRENDS OVER THE NEXT COUPLE OF HOURS.
HIGH ASTRONOMICAL TIDES DUE TO THE FULL MOON CYCLE AND FAVORABLE
NORTH/NORTHEAST WINDS COULD LEAD TO MINOR SALTWATER INUNDATION
NEAR THE COAST DURING THE HIGH TIDE CYCLES THROUGH THE WEEKEND. BY
THE TIME OF THE HIGH TIDE SUNDAY EVENING AND MONDAY
EVENING...WINDS WILL NOT BE AS CONDUCIVE...YET MINOR SALTWATER
FLOODING WILL STILL BE POSSIBLE AS ASTRONOMICAL FACTORS WILL CAUSE
HIGHER THAN TYPICAL TIDES. COASTAL FLOOD ADVISORIES MAY EVENTUALLY
BE NEEDED.
&&
.CLIMATE...
RECORD LOW TEMPERATURES FOR MAY 25TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....47 SET IN 1967
DOWNTOWN CHARLESTON /KCHL/..................54 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1967
RECORD LOW TEMPERATURES FOR MAY 26TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....50 SET IN 1979
DOWNTOWN CHARLESTON /KCHL/..................50 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1979
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT
SATURDAY FOR AMZ350-352-354-374.
&&
$$
SYNOPSIS...
NEAR TERM...BSH
SHORT TERM...RFM
LONG TERM...RJB
AVIATION...BSH
MARINE...BSH/RFM
TIDES/COASTAL FLOODING...
CLIMATE...
000
FXUS62 KGSP 241813
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
213 PM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL MOVE OFF THE ATLANTIC COAST TONIGHT AND
SATURDAY WHILE SURFACE HIGH PRESSURE CONTINUES THE COOLER THAN
NORMAL TEMPERATURES THIS WEEKEND. EXPECT AFTERNOON SHOWERS AND
THUNDERSTORMS NEXT WEEK...MAINLY OVER THE MOUNTAINS. A RATHER STRONG
UPPER RIDGE WILL BRING VERY WARM TEMPERATURES FOR THE SECOND HALF
OF THE WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF MID AFTERNOON...GUSTY NW WINDS WILL CONTINUE THROUGH SUNSET
WITH A FEW CLOUDS...OTHERWISE COOL AND DRY LIKE LATE APRIL.
FOR TONIGHT...AN UPPER TROF AXIS WILL SWING OFF THE EAST COAST
LEAVING BEHIND A DEEP NW FLOW THAT WILL BRING DOWN HIGH PRESSURE AND
COOL TEMPS...MORE THAN TEN DEGREES BELOW NORMAL. THE WIND SHOULD
DIMINISH SIGNIFICANTLY BY EARLY SATURDAY MORNING. THIS COULD BE
ENOUGH TO ALLOW FOR PATCHY FROST TO DEVELOP IN SOME OF THE SHELTERED
MOUNTAIN VALLEYS...PARTICULARLY THE LITTLE TN RIVER VALLEY. THE AREA
IMPACTED DOES NOT LOOK LARGE ENOUGH FOR A FROST ADVISORY SO THE
MENTION WILL REMAIN RELEGATED TO THE HWO.
SATURDAY IS SHAPING UP TO BE A BRIGHT...SUNNY...COOL...AND DRY DAY
WITH A LIGHT BREEZE...COURTESY OF SURFACE HIGH PRESSURE RIDGING DOWN
FROM THE GREAT LAKES. CHAMBER OF COMMERCE WEATHER FOR THE FIRST PART
OF MEMORIAL DAY WEEKEND. OPEN UP THE WINDOWS AND ENJOY IT NOW
BECAUSE IT WILL NOT LAST. TEMPS WERE KEPT CLOSE TO A GUIDANCE
BLEND...WHICH IS A COMFORTABLE FIVE DEGREES OR SO BELOW NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM FRIDAY...NW FLOW ALOFT WILL CONTINUE THROUGH SUNDAY AS
AN INTENSE UPPER LOW MOVES THROUGH NEW ENGLAND. THE FLOW WILL
DE-AMPLIFY ON MONDAY WITH BUILDING HEIGHTS AS THE LOW MOVES OUT THE
PICTURE. AT THE SURFACE...HIGH PRESSURE WILL RIDGE SOUTH FROM THE
SOUTHERN GREAT LAKES WITH A WEAK BACKDOOR FRONT MOVING THROUGH THE
AREA ON SUNDAY. THIS FRONT WILL MOVE NORTH AS A WARM FRONT ON
MONDAY. A MORE DOMINATE HIGH IS FORECAST TO DEVELOP OFF THE SE COAST
ON MONDAY.
A SERIES OF IMPULSES EMBEDDED IN THE NW FLOW ARE FORECAST TO MOVE
ACROSS THE AREA SUNDAY AND MONDAY. THE AIRMASS OVER THE REGION WILL
BE QUITE DRY IN THE LOWER LEVELS INITIALLY WITH DEWPOINTS IN THE 30S
AND 40S ON SUNDAY. HENCE...THE LACK OF SIGNIFICANT QPF RESPONSE IN
THE MODEL FORECASTS FOR SUN/SUN NIGHT IS NOT SURPRISING. WOULD EXPECT
THAT ANY PRECIP THAT FALLS SUNDAY AND SUNDAY NIGHT WILL BE MAINLY
VIRGA OR PERHAPS SOME SPRINKLES IN THE MOUNTAINS. MONDAY IS A
SLIGHTLY DIFFERENT STORY AS LOW LEVEL MOISTURE IMPROVES WITH
DEWPOINTS RISING INTO THE 50S AS THE WARM FRONT LIFTS NE.
THEREFORE...WOULD EXPECT SOME SCATTERED SHOWERS DEVELOPING IN THE
MOUNTAINS IN THE MORNING...WITH SCATTERED SHOWERS AND PERHAPS EVEN
SOME THUNDERSTORMS IN THE AFTERNOON....MAINLY OVER THE MOUNTAINS AND
THE NC FOOTHILLS/PIEDMONT.
TEMPERATURES WILL BE BELOW AVERAGE SAT NIGHT AND SUNDAY...WITH
MODERATING TEMPS ON MONDAY APPROACHING SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 150 PM FRIDAY...STARTING AT 00Z TUESDAY ALL MODELS SHOW SOME
MID LEVEL MOISTURE BETWEEN THE DEPARTING UPPER TROUGH WITH AXIS JUST
OFF THE NEW ENGLAND COAST AND THE EXPANDING UPPER RIDGE WITH AXIS
OVER EAST TEXAS. THIS LINEAR AREA OF MOISTURE EXTENDS FROM KY TO NC
MONDAY NIGHT THEN SHIFTS EAST AS RIDGE BUILDS FROM SW. SOUTHWESTERLY
LOW LEVEL FLOW WILL BRING WARMER AIR INTO THE REGION AS TEMPERATURES
WILL BE A LITTLE ABOVE NORMAL TUESDAY AND WEDNESDAY AND THEN TWO
CATEGORIES ABOVE NORMAL FOR HIGHS THURSDAY AND FRIDAY. INSTABILITY
WILL SUPPORT PM SHOWERS AND STORMS BUT FAVORING DIFFERENTIAL HEATING
OF THE MOUNTAINS. CAPE VALUES ARE MOST UNSTABLE ON ECMWF WITH 1000
TO 2000 VALUES EACH AFTERNOON. GFS IS MORE REASONABLE WITH 800 TO
1200 TUES...DROPPING TO LESS THAN 1000 FOR THE REST OF THE WEEK WITH
HIGHEST VALUES NORTH OF CLT TOWARD VA. MODELS HAVE CENTER OF 500MB
RIDGE OVER WESTERN NC THURSDAY. SEEMS MORE STABLE ON THURSDAY AND
EVEN MORE STABLE FRIDAY WITH DRIER LOW TO MID LEVEL. UPPER RIDGE
BEGINS TO MOVE OFF THE EAST COAST GOING INTO NEXT WEEKEND.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR THROUGH THE PERIOD. A FEW STRATOCU WITH
BASES AT 050 TO 060 THROUGH SUNSET...THEN CLEAR AFTER 01Z. WIND WILL
REMAIN GUSTY FROM THE NW THROUGH SUNSET BUT WILL QUICKLY DIMINISH
AFTER THAT AS THE CENTER OF THE HIGH BUILDS IN. MOST PLACES WILL GO
LIGHT AND VARIABLE EARLY SATURDAY MORNING AND STAY THAT WAY THROUGH
THE REST OF THE TAF PERIOD...THE EXCEPTION BEING KAVL WHERE A NW
UPVALLEY WIND WILL BE MAINTAINED. COULD BE SOME FOG OR FROST IN THE
LITTLE TN RIVER VALLEY AROUND DAYBREAK SATURDAY...BUT NOT AROUND
KAVL.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED. A
RETURN TO DIURNAL THUNDERSTORMS IS EXPECTED FOR MONDAY THROUGH
WEDNESDAY WITH ASSOCIATED RESTRICTIONS IN THE VICINITY OF STORMS.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA THIS AFTERNOON. AFTERNOON MINIMUM RELATIVE
HUMIDITY VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...PM
SHORT TERM...LG
LONG TERM...DEO
AVIATION...PM
FIRE WEATHER...
000
FXUS62 KCHS 241753
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
153 PM EDT FRI MAY 24 2013
.SYNOPSIS...
A REINFORCING COLD FRONT WILL MOVE THROUGH LATE THIS AFTERNOON
AND EARLY THIS EVENING. HIGH PRESSURE WILL THEN BUILD INTO THE
REGION THROUGH NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY THIS AFTERNOON...ONLY MADE MINOR TWEAKS TO HOURLY GRIDS.
PREVIOUS DISCUSSION FOLLOWS BELOW.
LATE THIS MORNING...CLEAR SKIES DOMINATE THE REGION AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. A REINFORCING BOUNDARY WILL
PUSH THROUGH SHORTLY AND IS EVIDENT IN UPSTREAM OBS WHICH SHOW
WINDS GUSTING INTO THE 20-25 KT RANGE. ALOFT...A SHARP MID/UPPER
LEVEL SHORTWAVE WILL DIVE OUT OF THE GREAT LAKES REGION TOWARDS
THE MID-ATLANTIC INTO THE EVENING. OTHER THAN SOME MID LEVEL
CLOUDS ASSOCIATED WITH THIS SHORTWAVE...THE DAY WILL FEATURE
MOSTLY SUNNY SKIES AND TEMPS WARMING NICELY IN THE DOWNSLOPE FLOW.
TEMPS WILL WARM INTO THE MID/UPPER 80S AND DEEP DRY AIR FILTERING
IN WILL KEEP THE FORECAST DRY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...THE UPPER LEVEL TROUGH WILL BEGIN TO SHIFT OFF THE MID-
ATLANTIC COAST THIS EVENING THEN PROGRESS OFFSHORE OVERNIGHT. A
REINFORCING COLD FRONT WILL COMPLETE ITS PASSAGE ACROSS THE AREA
DURING THE EARLY EVENING...WITH A NORTHERLY FLOW DEVELOPING IN ITS
WAKE AS HIGH PRESSURE BUILDS FROM THE GREAT LAKES REGION. THE
REINFORCING COLD FRONT WILL USHER IN A SIGNIFICANTLY DRIER AND
COOLER AIRMASS. THE COLD AIR ADVECTION WILL CAUSE TEMPERATURES TO
PLUMMET INTO THE UPPER 40S TO LOWER 50S AWAY FROM THE IMMEDIATE
COAST...WITH SOME MID 40S POSSIBLE WELL INLAND IF WINDS FULLY
DECOUPLE.
SATURDAY THROUGH MONDAY...MEDIUM RANGE GUIDANCE IS IN PRETTY GOOD
AGREEMENT THIS PERIOD SHOWING THE UPPER TROUGH SHIFTING OFFSHORE
WITH THE SURFACE HIGH TO FOLLOW. THIS WILL KEEP A DRY AND COOLER
THAN NORMAL AIR MASS IN PLACE. DEEP MOISTURE AND FORCING FOR
ASCENT WILL BE LACKING SO RAINFALL IS NOT EXPECTED THROUGH THE
PERIOD. THE BEST CHANCE OF ISOLATED SHOWERS WILL LIKELY COME
MONDAY AFTERNOON...MAINLY NORTH OF CHARLESTON...AS THE SEA BREEZE
PUSHES INLAND IN AN AXIS OF SLIGHTLY DEEPER MOISTURE.
WITH THE VERY DRY AIRMASS IN PLACE...TEMPERATURES WILL VARY ABOUT
25-30 DEGREES FROM THE MORNING LOWS TO THE AFTERNOON HIGHS. MORNING
LOWS SUNDAY COULD GET WITHIN A FEW DEGREES OF THE RECORDS AT
CHARLESTON AND SAVANNAH.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
DECENT MODEL AGREEMENT THIS PERIOD WITH ABOVE AVERAGE FORECAST
CONFIDENCE. UPPER HIGH PRESSURE SHOULD BUILD ACROSS THE REGION
TOWARD THE MIDDLE OF NEXT WEEK LEADING TO WARMING TEMPERATURES AND
SLOWLY INCREASING LOW-LEVEL MOISTURE. RAIN CHANCES WILL REMAIN LOW
GIVEN THE LACK OF DEEP MOISTURE AND FORCING...MAINLY CONFINED TO
INLAND AREAS DURING AFTERNOON PEAK HEATING AS THE SEA BREEZE PUSHES
INLAND.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH 18Z SATURDAY. GUSTY NW WINDS
WILL DIMINISH THIS EVENING WITH THE LOSS OF HEATING...AND THEN
WINDS WILL VEER AROUND TO MORE NORTHERLY OVERNIGHT.
EXTENDED AVIATION...VFR CONDITIONS SHOULD PREVAIL.
&&
.MARINE...
TODAY...A WEAK COLD FRONT WILL MOVE OFFSHORE THIS MORNING WITH
NORTHWEST WINDS PREVAILING ACROSS THE WATERS. WIND SPEEDS WILL
GENERALLY BE IN THE 10-15 KT RANGE WITH SEAS NO HIGHER THAN 2-4
FT DUE TO THE LIMITED OFFSHORE FETCH.
TONIGHT...A REINFORCING COLD FRONT WILL MOVE THROUGH EARLY THIS
EVENING...WITH A STRONG NORTHERLY SURGE DEVELOPING IN ITS WAKE.
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE OUTER GEORGIA
WATERS DUE TO THE ELEVATED WINDS/SEAS ASSOCIATED WITH THE
NORTHERLY SURGE. CONDITIONS WILL BE NEAR SMALL CRAFT ADVISORY
LEVELS WITHIN 20 NM OF THE COAST...ESPECIALLY IN GEORGIA...HOWEVER
CONFIDENCE IS TOO LOW GIVEN THE MARGINAL CONDITIONS TO ISSUE ANY
ADDITIONAL SMALL CRAFT ADVISORIES AT THIS TIME.
SATURDAY THROUGH WEDNESDAY...HIGH PRESSURE WILL MOVE OFFSHORE EARLY
NEXT WEEK AND PERSIST THROUGH MID WEEK. ENHANCED WINDS/SEAS EARLY
SATURDAY WILL DIMINISH DURING THE DAY AS THE HIGH GAINS MORE
INFLUENCE AND THE PRESSURE GRADIENT SLACKENS. A MORE TYPICAL
SPRINGTIME PATTERN WILL DOMINATE THEREAFTER WITH SOME WIND
ENHANCEMENT DURING THE DAY NEAR THE COAST AS THE SEA BREEZE DEVELOPS
AND THEN OFFSHORE OVERNIGHT WITH NOCTURNAL SURGING.
HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS
THROUGH THE PERIOD.
RIP CURRENTS...THE COMBINATION OF ASTRONOMICAL INFLUENCES AND AN 8
SECOND LONG PERIOD SWELL WILL RESULT IN A MODERATE RISK OF RIP
CURRENTS AT AREA BEACHES TODAY. THE ENHANCED RIP CURRENT RISK MAY
PERSIST INTO SATURDAY.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE THIS EVENING AND AGAIN SATURDAY EVENING. BY THE TIME OF THE
HIGH TIDE SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE AS
ASTRONOMICAL FACTORS WILL CAUSE HIGHER THAN TYPICAL TIDES.
&&
.CLIMATE...
RECORD LOW TEMPERATURES FOR MAY 25TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....47 SET IN 1967
DOWNTOWN CHARLESTON /KCHL/..................54 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1967
RECORD LOW TEMPERATURES FOR MAY 26TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....50 SET IN 1979
DOWNTOWN CHARLESTON /KCHL/..................50 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1979
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT
SATURDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...BSH
SHORT TERM...JAQ/RJB
LONG TERM...RJB
AVIATION...BSH
MARINE...JAQ/RJB
TIDES/COASTAL FLOODING...
CLIMATE...
000
FXUS62 KGSP 241733
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
133 PM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL MOVE OFF THE ATLANTIC COAST TONIGHT AND
SATURDAY WHILE SURFACE HIGH PRESSURE CONTINUES THE COOLER THAN
NORMAL TEMPERATURES THIS WEEKEND. EXPECT AFTERNOON SHOWERS AND
THUNDERSTORMS NEXT WEEK...MAINLY OVER THE MOUNTAINS. A RATHER STRONG
UPPER RIDGE WILL BRING VERY WARM TEMPERATURES FOR THE SECOND HALF
OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF EARLY AFTERNOON...THE FCST IS ON TRACK WITH TEMPS AND WITH
GUSTY NW WIND REMAINING BELOW ADVISORY LEVELS. NO CHANGES.
REMAINDER OF PREVIOUS DISCUSSION...
TODAY...DRY HIGH PRES WILL BEGIN TO CONTINUE BUILD INTO THE AREA
FROM THE NW. MOST OF THE GUIDANCE...THE NAM IN PARTICULAR...INDICATE
BREEZY TO WINDY CONDITIONS ACRS THE CWFA. IN FACT...THE HIGH TERRAIN
AND SOME OF THE VALLEYS WHERE A GAP WIND WILL SET UP MAY APPROACH
WIND ADV CRITERIA...MAINLY DURING THE MORNING HOURS. CONFIDENCE NOT
HIGH ENUF TO GO WITH A WIND ADV IN THE MTNS. ELSEWHERE...BREEZY
CONDITIONS WARRANTS CAUTION ON AREA LAKES. TEMPS WILL BE BELOW
NORMAL UNDER SUNNY TO MOSTLY SUNNY SKIES.
TONIGHT...THE SFC HIGH WILL STILL BE CENTERED TO OUR NW...SO MIXING
IS EXPECTED TO CONTINUE THRU THE NIGHT. CLEAR SKIES AND CAA WILL
ALLOW TEMPS TO DROP INTO THE 30S IN THE MTNS AND 40S ACRS MOST OF
THE PIEDMONT. PATCHY FROST IS POSSIBLE IN THE SHELTERED
VALLEYS...BUT WIDESPREAD FROST IS NOT EXPECTED DUE TO THE MIXING
ACRS THE HIGH TERRAIN.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 200 PM FRIDAY...NW FLOW ALOFT WILL CONTINUE THROUGH SUNDAY AS
AN INTENSE UPPER LOW MOVES UP THE EAST COAST. THE FLOW WILL
DE-AMPLIFY ON MONDAY WITH BUILDING HEIGHTS AS THE LOW MOVES OUT THE
PICTURE. AT THE SURFACE...HIGH PRESSURE WILL WILL RIDGE SOUTH FROM
THE SOUTHERN GREAT LAKES WITH A WEAK BACKDOOR FRONT MOVING THROUGH
THE AREA ON SUNDAY. THIS FRONT WILL MOVE NORTH AS A WARM FRONT ON
MONDAY. A MORE DOMINATE HIGH IS FORECAST TO DEVELOP OFF THE SE COAST
ON MONDAY.
A SERIES OF IMPULSES EMBEDDED IN THE NW FLOW ARE FORECAST TO MOVE
ACROSS THE AREA SUNDAY AND MONDAY. THE AIRMASS OVER THE REGION WILL
BE QUITE DRY IN THE LOWER LEVELS INITIALLY WITH DEWPOINTS IN THE 30S
AND 40S ON SUNDAY. HENCE...THE LACK OF SIGNIFICANT QPF RESPONSE IN
THE MODEL FORECASTS FOR SUNDAY IS NOT SURPRISING. WOULD EXPECT THAT
ANY PRECIP THAT FALLS SUNDAY AND SUNDAY NIGHT WILL BE MAINLY VIRGA
OR PERHAPS SOME SPRINKLES IN THE MOUNTAINS. MONDAY IS A DIFFERENT
STORY AS LOW LEVEL MOISTURE IMPROVES WITH DEWPOINGS RISING INTOT EH
50S AS THE WARM FRONT LIFTS NE. THEREFORE...WOULD EXPECT SOME
SCATTERED SHOWERS DEVELOPING INT HE MOUNTAINS IN THE MORNING...WITH
SCATTERED SHOWERS AND PERHAPS EVEN SOME THUNDERSTORMS IN THE
AFTERNOON....MAINLY OVER THE MOUNTAINS AND THE NC
FOOTHILLS/PIEDMONT.
TEMPERATURES WILL BE WELL BELOW AVERAGE THROUGH SAT NIGHT AND
SUNDAY...WITH MODERATING TEMPS ON MONDAY APPROACHING SEASONAL
LEVELS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE EXTENDED FORECAST LOOKS GOOD AND NO MAJOR
CHANGES HAVE BEEN MADE TO THE GRIDS. THE 00 UTC GFS AND YDAYS 12 UTC
ECMWF ARE IN GOOD AGREEMENT IN GRADUALLY BUILDING A LONG WAVE RIDGE
ACROSS THE LOWER MS RIVER VALLEY AND DEEP SOUTH STATES THROUGH THE
PERIOD. WE WILL START OUT THE PERIOD UNDER NW FLOW ON THE BACK SIDE
OF A LARGE LONG WAVE RIDGE CENTERED OVER THE WRN ATLANTIC. THE
MODELS HAVE QUITE A BIT OF MID AND UPPER LEVEL MOISTURE ON THE BACK
SIDE OF THE TROUGH...THE RESULT OF LOW AND MID LEVEL ISENTROPIC
UPGLIDE. STILL...THE SFC DEWPOINTS ARE LOW AND PCPN CHANCES MONDAY
SHOULD MAINLY BE CONFINED TO SPRINKLES OR LIGHT HIGH-BASED SHOWERS
OVER THE MTNS. TUE THROUGH THU BNDRY LAYER MOISTURE INCREASES AS THE
SFC RIDGE AXIS MOVES OFF THE COAST. THE GFS HAS THE BEST INSTABILITY
BY FAR OVER THE MOUNTAINS TUE AND WED...WITH A LITTLE MORE DRYING ON
FRI. AT THIS POINT LOW CHANCE POPS OVER THE MTNS AND SLIGHT CHANCE
POPS ELSEWHERE ALL THREE DAYS STILL LOOKS GOOD. I DID NUDGE TEMPS UP
A LITTLE TUE. I THINK WED AND THU ARE PROBABLY A LITTLE TOO
COOL...BUT I/LL LEAVE THAT FOR THE DAY SHIFT TO DECIDE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR THROUGH THE PERIOD. A FEW STRATOCU WITH
BASES AT 050 TO 060 THROUGH SUNSET...THEN CLEAR AFTER 01Z. WIND WILL
REMAIN GUSTY FROM THE NW THROUGH SUNSET BUT WILL QUICKLY DIMINISH
AFTER THAT AS THE CENTER OF THE HIGH BUILDS IN. MOST PLACES WILL GO
LIGHT AND VARIABLE EARLY SATURDAY MORNING AND STAY THAT WAY THROUGH
THE REST OF THE TAF PERIOD...THE EXCEPTION BEING KAVL WHERE A NW
UPVALLEY WIND WILL BE MAINTAINED. COULD BE SOME FOG OR FROST IN THE
LITTLE TN RIVER VALLEY AROUND DAYBREAK SATURDAY...BUT NOT AROUND
KAVL.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED. A
RETURN TO DIURNAL THUNDERSTORMS IS EXPECTED FOR MONDAY THROUGH
WEDNESDAY WITH ASSOCIATED RESTRICTIONS IN THE VICINITY OF STORMS.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-17Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA TODAY. AFTERNOON MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS
TODAY. IF ANY LAND MANAGEMENT OFFICIALS THINK THAT A FIRE DANGER
STATEMENT IS WARRANTED PLEASE CONTACT OUR OFFICE.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK/PM
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...PM
FIRE WEATHER...
000
FXUS62 KCAE 241732
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
132 PM EDT FRI MAY 24 2013
.SYNOPSIS...
COOL HIGH PRESSURE WILL SETTLE OVER THE REGION FOR THE
WEEKEND...BRINGING BELOW NORMAL TEMPERATURES AND DRY WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION FROM THE
NORTHWEST WITH WEAK COLD ADVECTION CONTINUING THROUGH TONIGHT.
BREEZY AFTERNOON CONDITIONS WILL RELAX WITH SUNSET WITH THE LOSS
OF DIURNAL HEATING AND WEAKENING PRESSURE GRADIENT. PRECIPITABLE
WATER VALUES WILL FALL BELOW A HALF INCH OVERNIGHT AND DEWPOINTS
WILL FALL INTO THE 40S...LEADING TO LOW FOG POTENTIAL.
NOT EXACTLY AN IDEAL RADIATIONAL COOLING SCENARIO TONIGHT ALTHOUGH
WINDS ARE LIKELY TO FALL TO NEAR CALM DURING THE PREDAWN HOURS ON
SATURDAY WHICH COULD ALLOW SOME OF THE OUTLYING AREAS TO DROP
SEVERAL DEGREES JUST BEFORE SUNRISE. WELL BELOW NORMAL
TEMPERATURES EXPECTED WITH POSSIBLE RECORD LOWS BEING REACHED IF
WINDS GO CALM EARLIER THAN EXPECTED AND DEWPOINTS DROP LOWER THAN
FORECAST. THINK LOWS WILL REMAIN A DEGREE OR TWO ABOVE RECORD
VALUES THOUGH.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
MODELS IN GOOD AGREEMENT SATURDAY THROUGH SUNDAY NIGHT. SHORT WAVE
EXITS TO THE EAST SATURDAY AS COOL HIGH PRESSURE BUILDS ACROSS THE
REGION THROUGH SATURDAY NIGHT. AIRMASS BEGINS TO MODIFY BY SUNDAY
AS OLD FRONTAL BOUNDARY TO THE SOUTH RETURNS NORTHWARD AS A WARM
FRONT. MOSTLY CLEAR SATURDAY BUT MORE CLOUDS BY SUNDAY BUT NO RAIN
AS ATMOSPHERE IS STILL DRY BOTH SUNDAY AND SUNDAY NIGHT. COOL
SATURDAY WITH HIGHS IN THE UPPER 70S...INCREASE TO THE LOWER 80S
BY SUNDAY. STILL COOL SATURDAY NIGHT BUT NOT AS COOL AS FRIDAY
NIGHT WITH LOWS IN THE UPPER 40S TO LOWER 50S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT SHOWING UPPER RIDGE
OVER THE MISSISSIPPI VALLEY MONDAY BUILDING EASTWARD ACROSS THE
REGION THROUGH THURSDAY. THE RIDGE BEGINS TO MOVE MORE TOWARD THE
EAST COAST FRIDAY. ALSO...A WARM FRONTAL BOUNDARY ACROSS THE
FORECAST AREA MONDAY LIFTS TO THE NORTHEAST AND AWAY FROM THE AREA
TUESDAY THROUGH FRIDAY. THIS UPPER RIDGE IS EXPECTED TO HOLD ANY
FRONTS WELL TO THE NORTH AND WEST DURING THE EXTENDED PERIOD.
SOUTH TO SOUTHWEST LOW LEVEL WIND FLOW WILL BRING MORE WARM
UNSTABLE AIR TO THE REGION AND THE ATMOSPHERE WILL BECOME
CONDITIONALLY UNSTABLE. STILL DRY MONDAY THOUGH BUT INCLUDED
DIURNAL CONVECTIVE ACTIVITY TUESDAY THROUGH THURSDAY. UPPER RIDGE
PRETTY STRONG AND JUST ABOUT RIGHT OVER THE AREA FRIDAY...SO LEFT
DRY FOR FRIDAY AS WELL. HIGHS IN THE MID 80S MONDAY AND TUESDAY
AND THE MID TO UPPER 80S WEDNESDAY THROUGH FRIDAY. OVERNIGHT LOWS
MAINLY IN THE LOWER 60S.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
NORTHWESTERLY WINDS 10-20 MPH WITH GUSTS TO 25 MPH THROUGH THE
AFTERNOON BUT WINDS WILL WEAKEN AROUND SUNSET...REMAINING
NORTHERLY. NO FOG EXPECTED DUE TO DRY AIRMASS BUILDING INTO THE
REGION. CLEAR SKIES OVERNIGHT INTO SATURDAY MORNING WITH NORTHERLY
WINDS PICKING UP TO AROUND 5-10 MPH AFTER 14Z.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY THIS AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WIND APPEARS MARGINAL FOR A RED FLAG WARNING.
EXPECT GUSTS NEAR 25 MPH. FUEL MOISTURE IS HIGH REDUCING THE FIRE
THREAT.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES WILL OCCUR TONIGHT WITH LOWS IN
THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW FOR MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW FOR MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 241449
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1049 AM EDT FRI MAY 24 2013
.SYNOPSIS...
THE PRESSURE RIDGE IN THE MISSISSIPPI RIVER VALLEY TODAY WILL MOVE
EASTWARD. THE RIDGE WILL BE ALONG THE EAST COAST SATURDAY NIGHT
AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE COLD FRONT THAT PUSHED THROUGH EARLY THIS MORNING HAS SHIFTED
OFF THE COAST WHILE YET ANOTHER FRONT WITH COOLER AND DRIER AIR
CONTINUES TO MOVE THROUGH THE NC PIEDMONT AND UPSTATE SC. LATEST
SATELLITE IMAGERY SHOWING UPSLOPE CLOUDS ON THE WEST SIDE OF THE
MOUNTAINS WHILE SOME MID LEVEL CLOUDS CONTINUE TO MOVE OUT OF THE
PEE DEE REGION AND NEW CUMULUS DEVELOPMENT IS TAKING PLACE ACROSS
THE MIDLANDS. PRECIPITABLE WATER VALUES ARE DOWN TO 0.70 INCHES
AND WILL CONTINUE TO FALL THROUGH THE DAY AS HIGH PRESSURE BUILDS
INTO THE REGION. THERE REMAINS ENOUGH LOW LEVEL MOISTURE TO
SUPPORT THE CUMULUS DEVELOPMENT THAT IS OCCURRING ALTHOUGH THESE
CLOUDS SHOULD DIMINISH DURING THE AFTERNOON HOURS AS DRIER AIR
MOVES INTO THE REGION.
GUSTY NORTHWESTERLY WINDS EXPECTED TODAY UNDER MOSTLY SUNNY SKIES
AS THE UPPER TROUGH MOVES OFF THE EAST COAST BY THIS AFTERNOON.
TEMPERATURES ALREADY A FEW DEGREES ABOVE MOS FORECAST NUMBERS AND
WILL CONTINUE WITH CURRENT FORECAST HIGHS IN THE LOW TO MID
80S...AIDED BY DOWNSLOPING NORTHWESTERLY FLOW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE DRY PRESSURE RIDGE APPROACHING FROM THE WEST WILL DOMINATE
THROUGH SATURDAY NIGHT. BELOW NORMAL TEMPERATURES WILL BE
ASSOCIATED WITH THIS AIR MASS. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST. EXPECT LOWS IN THE 40S TONIGHT. SATURDAY
NIGHT SHOULD NOT BE QUITE AS COOL BECAUSE OF AIR MASS
MODIFICATION.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH AN UPPER RIDGE
WORKING INTO THE FORECAST AREA FROM THE WEST. THE GFS AND ECMWF
SHOW A WEAK SURFACE FRONTAL BOUNDARY WHICH REMAINS MAINLY TO THE
NORTH BUT THE ECMWF SHOWS THE FRONT A LITTLE STRONGER COMPARED TO
THE GFS. THE ECMWF ALSO DISPLAYS THE FRONT FARTHER TO THE SOUTH.
IT SHOULD BE DRY TO START SUNDAY AND MONDAY BUT BY THE END OF THE
PERIOD...MOISTURE AND INSTABILITY WILL INCREASE. EXPECT DIURNAL
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY WITH COVERAGE LIMITED BY
THE UPPER RIDGING. THE GFS ENSEMBLE MEANS SUPPORT JUST SLIGHT
CHANCE POPS.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
BREEZY NORTHWESTERLY WINDS EXPECTED TODAY IN THE WAKE OF A COLD
FRONT THAT PUSHED THROUGH EARLIER THIS MORNING. EXPECTING 15 TO 20
MPH WINDS WITH SOME GUSTS UP TO 25 MPH. WINDS WILL DIMINISH BY 00Z
SATURDAY TO LESS THAN 10 KNOTS. NO FOG EXPECTED DUE TO DRY AIRMASS
BUILDING INTO THE REGION.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY THIS AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WIND APPEARS MARGINAL FOR A RED FLAG WARNING.
EXPECT GUSTS NEAR 25 MPH. FUEL MOISTURE IS HIGH REDUCING THE FIRE
THREAT.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES WILL OCCUR TONIGHT WITH LOWS IN
THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW FOR MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW FOR MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
NEAR TERM...HC
AVIATION...HC
000
FXUS62 KCHS 241445
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1045 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A REINFORCING COLD FRONT WILL MOVE THROUGH LATE THIS AFTERNOON
AND EARLY THIS EVENING. HIGH PRESSURE WILL THEN BUILD INTO THE
REGION THROUGH NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATE THIS MORNING...CLEAR SKIES DOMINATE THE REGION AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. A REINFORCING BOUNDARY WILL
PUSH THROUGH SHORTLY AND IS EVIDENT IN UPSTREAM OBS WHICH SHOW
WINDS GUSTING INTO THE 20-25 KT RANGE. ALOFT...A SHARP MID/UPPER
LEVEL SHORTWAVE WILL DIVE OUT OF THE GREAT LAKES REGION TOWARDS
THE MID-ATLANTIC INTO THE EVENING. OTHER THAN SOME MID LEVEL
CLOUDS ASSOCIATED WITH THIS SHORTWAVE...THE DAY WILL FEATURE
MOSTLY SUNNY SKIES AND TEMPS WARMING NICELY IN THE DOWNSLOPE FLOW.
TEMPS WILL WARM INTO THE MID/UPPER 80S AND DEEP DRY AIR FILTERING
IN WILL KEEP THE FORECAST DRY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...THE UPPER LEVEL TROUGH WILL BEGIN TO SHIFT OFF THE MID-
ATLANTIC COAST THIS EVENING THEN PROGRESS OFFSHORE OVERNIGHT. A
REINFORCING COLD FRONT WILL COMPLETE ITS PASSAGE ACROSS THE AREA
DURING THE EARLY EVENING...WITH A NORTHERLY FLOW DEVELOPING IN ITS
WAKE AS HIGH PRESSURE BUILDS FROM THE GREAT LAKES REGION. THE
REINFORCING COLD FRONT WILL USHER IN A SIGNIFICANTLY DRIER AND
COOLER AIRMASS. THE COLD AIR ADVECTION WILL CAUSE TEMPERATURES TO
PLUMMET INTO THE UPPER 40S TO LOWER 50S AWAY FROM THE IMMEDIATE
COAST...WITH SOME MID 40S POSSIBLE WELL INLAND IF WINDS FULLY
DECOUPLE.
SATURDAY THROUGH MONDAY...MEDIUM RANGE GUIDANCE IS IN PRETTY GOOD
AGREEMENT THIS PERIOD SHOWING THE UPPER TROUGH SHIFTING OFFSHORE
WITH THE SURFACE HIGH TO FOLLOW. THIS WILL KEEP A DRY AND COOLER
THAN NORMAL AIR MASS IN PLACE. DEEP MOISTURE AND FORCING FOR
ASCENT WILL BE LACKING SO RAINFALL IS NOT EXPECTED THROUGH THE
PERIOD. THE BEST CHANCE OF ISOLATED SHOWERS WILL LIKELY COME
MONDAY AFTERNOON...MAINLY NORTH OF CHARLESTON...AS THE SEA BREEZE
PUSHES INLAND IN AN AXIS OF SLIGHTLY DEEPER MOISTURE.
WITH THE VERY DRY AIRMASS IN PLACE...TEMPERATURES WILL VARY ABOUT
25-30 DEGREES FROM THE MORNING LOWS TO THE AFTERNOON HIGHS. MORNING
LOWS SUNDAY COULD GET WITHIN A FEW DEGREES OF THE RECORDS AT
CHARLESTON AND SAVANNAH.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
DECENT MODEL AGREEMENT THIS PERIOD WITH ABOVE AVERAGE FORECAST
CONFIDENCE. UPPER HIGH PRESSURE SHOULD BUILD ACROSS THE REGION
TOWARD THE MIDDLE OF NEXT WEEK LEADING TO WARMING TEMPERATURES AND
SLOWLY INCREASING LOW-LEVEL MOISTURE. RAIN CHANCES WILL REMAIN LOW
GIVEN THE LACK OF DEEP MOISTURE AND FORCING...MAINLY CONFINED TO
INLAND AREAS DURING AFTERNOON PEAK HEATING AS THE SEA BREEZE PUSHES
INLAND.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z SATURDAY.
EXTENDED AVIATION...VFR CONDITIONS SHOULD PREVAIL.
&&
.MARINE...
TODAY...A WEAK COLD FRONT WILL MOVE OFFSHORE THIS MORNING WITH
NORTHWEST WINDS PREVAILING ACROSS THE WATERS. WIND SPEEDS WILL
GENERALLY BE IN THE 10-15 KT RANGE WITH SEAS NO HIGHER THAN 2-4
FT DUE TO THE LIMITED OFFSHORE FETCH.
TONIGHT...A REINFORCING COLD FRONT WILL MOVE THROUGH EARLY THIS
EVENING...WITH A STRONG NORTHERLY SURGE DEVELOPING IN ITS WAKE.
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE OUTER GEORGIA
WATERS DUE TO THE ELEVATED WINDS/SEAS ASSOCIATED WITH THE
NORTHERLY SURGE. CONDITIONS WILL BE NEAR SMALL CRAFT ADVISORY
LEVELS WITHIN 20 NM OF THE COAST...ESPECIALLY IN GEORGIA...HOWEVER
CONFIDENCE IS TOO LOW GIVEN THE MARGINAL CONDITIONS TO ISSUE ANY
ADDITIONAL SMALL CRAFT ADVISORIES AT THIS TIME.
SATURDAY THROUGH WEDNESDAY...HIGH PRESSURE WILL MOVE OFFSHORE EARLY
NEXT WEEK AND PERSIST THROUGH MID WEEK. ENHANCED WINDS/SEAS EARLY
SATURDAY WILL DIMINISH DURING THE DAY AS THE HIGH GAINS MORE
INFLUENCE AND THE PRESSURE GRADIENT SLACKENS. A MORE TYPICAL
SPRINGTIME PATTERN WILL DOMINATE THEREAFTER WITH SOME WIND
ENHANCEMENT DURING THE DAY NEAR THE COAST AS THE SEA BREEZE DEVELOPS
AND THEN OFFSHORE OVERNIGHT WITH NOCTURNAL SURGING.
HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS
THROUGH THE PERIOD.
RIP CURRENTS...THE COMBINATION OF ASTRONOMICAL INFLUENCES AND AN 8
SECOND LONG PERIOD SWELL WILL RESULT IN A MODERATE RISK OF RIP
CURRENTS AT AREA BEACHES TODAY. THE ENHANCED RIP CURRENT RISK MAY
PERSIST INTO SATURDAY.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE THIS EVENING AND AGAIN SATURDAY EVENING. BY THE TIME OF THE
HIGH TIDE SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE AS
ASTRONOMICAL FACTORS WILL CAUSE HIGHER THAN TYPICAL TIDES.
&&
.CLIMATE...
RECORD LOW TEMPERATURES FOR MAY 25TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....47 SET IN 1967
DOWNTOWN CHARLESTON /KCHL/..................54 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1967
RECORD LOW TEMPERATURES FOR MAY 26TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....50 SET IN 1979
DOWNTOWN CHARLESTON /KCHL/..................50 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1979
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT
SATURDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...BSH
SHORT TERM...JAQ/RJB
LONG TERM...RJB
AVIATION...JAQ/RJB
MARINE...JAQ/RJB
TIDES/COASTAL FLOODING...
CLIMATE...
000
FXUS62 KGSP 241430
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1030 AM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TODAY...BRINGING
COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL
MODERATE BY THE BEGINNING OF NEXT WEEK...WITH A CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF MID MORNING...KMRX RADAR SHOWS LIGHT PRECIP ECHOES ON THE WANE
ALONG THE TN BORDER...SO IT WOULD APPEAR THAT ANY NW FLOW SHOWER
ACTIVITY IS ON SCHEDULE TO END DURING THE NEXT HOUR. SOME CLOUDINESS
WILL CONTINUE OVER THE HIGHER TERRAIN INTO THE EARLY AFTERNOON. THE
ONLY OTHER FEATURE OF INTEREST IS A PATCH OF CLOUDS MOVING ACROSS
METRO CLT...BUT THAT SHOULD ALSO MOVE OFF TO THE SOUTHEAST. TEMPS
LOOK OKAY FOR NOW...NO CHANGES TO THE HIGHS.
REMAINDER OF PREVIOUS DISCUSSION...
TODAY...DRY HIGH PRES WILL BEGIN TO CONTINUE BUILD INTO THE AREA
FROM THE NW. MOST OF THE GUIDANCE...THE NAM IN PARTICULAR...INDICATE
BREEZY TO WINDY CONDITIONS ACRS THE CWFA. IN FACT...THE HIGH TERRAIN
AND SOME OF THE VALLEYS WHERE A GAP WIND WILL SET UP MAY APPROACH
WIND ADV CRITERIA...MAINLY DURING THE MORNING HOURS. CONFIDENCE NOT
HIGH ENUF TO GO WITH A WIND ADV IN THE MTNS. ELSEWHERE...BREEZY
CONDITIONS WARRANTS CAUTION ON AREA LAKES. TEMPS WILL BE BELOW
NORMAL UNDER SUNNY TO MOSTLY SUNNY SKIES.
TONIGHT...THE SFC HIGH WILL STILL BE CENTERED TO OUR NW...SO MIXING
IS EXPECTED TO CONTINUE THRU THE NIGHT. CLEAR SKIES AND CAA WILL
ALLOW TEMPS TO DROP INTO THE 30S IN THE MTNS AND 40S ACRS MOST OF
THE PIEDMONT. PATCHY FROST IS POSSIBLE IN THE SHELTERED
VALLEYS...BUT WIDESPREAD FROST IS NOT EXPECTED DUE TO THE MIXING
ACRS THE HIGH TERRAIN.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...GENERALLY FAIR WEATHER SATURDAY THROUGH SUNDAY
NIGHT. CLOUD COVER WILL INCREASE SATURDAY NIGHT...WITH VARIABLY
CLOUDY CONDITIONS EXPECTED INTO SUNDAY NIGHT. THIS WILL BE THE
RESULT OF WARM ADVECTION ON THE BACK SIDE OF A STRONG LONG WAVE
TROUGH. OVERALL THE FORCING LOOKS WEAK AND MOST OF WHAT WE SHOULD
SEE DURING THIS PERIOD WILL BE AC/SC AND PERHAPS A FEW AREAS OF
HIGH-BASED SPRINKLES OR LIGHT SHOWERS...PARTICULARLY SATURDAY NIGHT.
MAX TEMPS SATURDAY WILL BE A COUPLE CATEGORIES BELOW
NORMAL...REBOUNDING A FEW DEGREES ON SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE EXTENDED FORECAST LOOKS GOOD AND NO MAJOR
CHANGES HAVE BEEN MADE TO THE GRIDS. THE 00 UTC GFS AND YDAYS 12 UTC
ECMWF ARE IN GOOD AGREEMENT IN GRADUALLY BUILDING A LONG WAVE RIDGE
ACROSS THE LOWER MS RIVER VALLEY AND DEEP SOUTH STATES THROUGH THE
PERIOD. WE WILL START OUT THE PERIOD UNDER NW FLOW ON THE BACK SIDE
OF A LARGE LONG WAVE RIDGE CENTERED OVER THE WRN ATLANTIC. THE
MODELS HAVE QUITE A BIT OF MID AND UPPER LEVEL MOISTURE ON THE BACK
SIDE OF THE TROUGH...THE RESULT OF LOW AND MID LEVEL ISENTROPIC
UPGLIDE. STILL...THE SFC DEWPOINTS ARE LOW AND PCPN CHANCES MONDAY
SHOULD MAINLY BE CONFINED TO SPRINKLES OR LIGHT HIGH-BASED SHOWERS
OVER THE MTNS. TUE THROUGH THU BNDRY LAYER MOISTURE INCREASES AS THE
SFC RIDGE AXIS MOVES OFF THE COAST. THE GFS HAS THE BEST INSTABILITY
BY FAR OVER THE MOUNTAINS TUE AND WED...WITH A LITTLE MORE DRYING ON
FRI. AT THIS POINT LOW CHANCE POPS OVER THE MTNS AND SLIGHT CHANCE
POPS ELSEWHERE ALL THREE DAYS STILL LOOKS GOOD. I DID NUDGE TEMPS UP
A LITTLE TUE. I THINK WED AND THU ARE PROBABLY A LITTLE TOO
COOL...BUT I/LL LEAVE THAT FOR THE DAY SHIFT TO DECIDE.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR WITH SOME LINGERING MID CLOUDS THRU ABOUT 14Z. A NW
WIND EXPECTED THRU THE PERIOD...INCREASING INTO THE 10-15 KT RANGE
BY MID MORNING...WITH GUSTS IN THE 20-25 KT RANGE EXPECTED THRU THE
AFTN. WINDS DIMINISH AROUND SUNSET THIS EVENING.
AT KAVL...STRONG CHANNELED VALLEY WINDS WILL CONTINUE THRU THE DAY.
GENERALLY SUSTAINED 15-20 KTS AND GUSTS POSSIBLY IN THE 30-35 KT
RANGE. SOME MOISTURE WILL CONTINUE TO WORK UP THE VALLEY THRU ABOUT
MID MORNING...WITH ANY CIGS EXPECTED TO BE VFR. HOWEVER...BRIEF
PERIODS OF MVFR CIGS ARE POSSIBLE. SO WILL HAVE TEMPO FOR A COUPLE
HOURS. WINDS WILL BEGIN TO DIMINISH AFTER SUNSET THIS EVENING.
ELSEWHERE...VFR CONDITIONS ARE EXPECTED AT ALL OTHER TAF SITES THRU
THE PERIOD. WINDS WILL BE THE MAIN CONCERN TODAY. EXPECTING ALL
SITES TO HAVE WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS
FROM LATE MORNING THRU THE AFTN.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 99% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA TODAY. AFTERNOON MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS
TODAY. IF ANY LAND MANAGEMENT OFFICIALS THINK THAT A FIRE DANGER
STATEMENT IS WARRANTED PLEASE CONTACT OUR OFFICE.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK/PM
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...ARK
FIRE WEATHER...
000
FXUS62 KCHS 241141
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
741 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE OFFSHORE THIS MORNING...FOLLOWED BY A
REINFORCING COLD FRONT LATE THIS AFTERNOON AND EARLY THIS EVENING.
HIGH PRESSURE WILL THEN BUILD INTO THE REGION THROUGH NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
WATER VAPOR IMAGERY THIS MORNING DEPICTS A BROAD UPPER LEVEL
TROUGH CENTERED OVER THE GREAT LAKES REGION. MEANWHILE AT THE
SURFACE...A COLD FRONT HAS ENTERED WESTERN PORTIONS OF THE
FORECAST AREA AS OF 7 AM...WITH A SECONDARY/REINFORCING COLD FRONT
NOTED ACROSS THE CENTRAL APPALACHIANS AND TENNESSEE VALLEY.
AS THE DAY PROGRESSES...THE UPPER LEVEL TROUGH WILL DIG ACROSS
THE MID-ATLANTIC REGION. THIS WILL PUSH THE PRIMARY COLD FRONT
OFFSHORE LATER THIS MORNING...WITH THE SECONDARY/REINFORCING COLD
FRONT THEN EXPECTED TO SHIFT INTO THE AREA LATE THIS AFTERNOON AS
THE TROUGH AXIS CROSSES.
THE DRY WESTERLY FLOW IN PLACE AHEAD OF THE PRIMARY COLD FRONT
WILL PREVENT ANY SHOWERS FROM FORMING AS IT MOVES THROUGH...WITH
THE FLOW THEN VEERING NORTHWEST INTO THIS AFTERNOON. THERE COULD
BE SOME SCATTERED MID LEVEL CLOUDS BENEATH THE UPPER TROUGH...ESPECIALLY
OVER SOUTHEAST SOUTH CAROLINA...BUT A GOOD AMOUNT OF SUNSHINE AND
A STRONG DOWNSLOPE FLOW WILL SUPPORT HIGHS IN THE MID TO UPPER 80S
ACROSS THE AREA AWAY FROM THE IMMEDIATE COAST. DEEP MIXING THIS
AFTERNOON WILL SUPPORT BREEZY CONDITIONS...WITH WINDS AS HIGH AS
15-20 MPH WITH GUSTS TO 25 MPH AT TIMES.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
TONIGHT...THE UPPER LEVEL TROUGH WILL BEGIN TO SHIFT OFF THE MID-
ATLANTIC COAST THIS EVENING THEN PROGRESS OFFSHORE OVERNIGHT. A
REINFORCING COLD FRONT WILL COMPLETE ITS PASSAGE ACROSS THE AREA
DURING THE EARLY EVENING...WITH A NORTHERLY FLOW DEVELOPING IN ITS
WAKE AS HIGH PRESSURE BUILDS FROM THE GREAT LAKES REGION. THE
REINFORCING COLD FRONT WILL USHER IN A SIGNIFICANTLY DRIER AND
COOLER AIRMASS. THE COLD AIR ADVECTION WILL CAUSE TEMPERATURES TO
PLUMMET INTO THE UPPER 40S TO LOWER 50S AWAY FROM THE IMMEDIATE
COAST...WITH SOME MID 40S POSSIBLE WELL INLAND IF WINDS FULLY
DECOUPLE.
SATURDAY THROUGH MONDAY...MEDIUM RANGE GUIDANCE IS IN PRETTY GOOD
AGREEMENT THIS PERIOD SHOWING THE UPPER TROUGH SHIFTING OFFSHORE
WITH THE SURFACE HIGH TO FOLLOW. THIS WILL KEEP A DRY AND COOLER
THAN NORMAL AIR MASS IN PLACE. DEEP MOISTURE AND FORCING FOR
ASCENT WILL BE LACKING SO RAINFALL IS NOT EXPECTED THROUGH THE
PERIOD. THE BEST CHANCE OF ISOLATED SHOWERS WILL LIKELY COME
MONDAY AFTERNOON...MAINLY NORTH OF CHARLESTON...AS THE SEA BREEZE
PUSHES INLAND IN AN AXIS OF SLIGHTLY DEEPER MOISTURE.
WITH THE VERY DRY AIRMASS IN PLACE...TEMPERATURES WILL VARY ABOUT
25-30 DEGREES FROM THE MORNING LOWS TO THE AFTERNOON HIGHS. MORNING
LOWS SUNDAY COULD GET WITHIN A FEW DEGREES OF THE RECORDS AT
CHARLESTON AND SAVANNAH.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
DECENT MODEL AGREEMENT THIS PERIOD WITH ABOVE AVERAGE FORECAST
CONFIDENCE. UPPER HIGH PRESSURE SHOULD BUILD ACROSS THE REGION
TOWARD THE MIDDLE OF NEXT WEEK LEADING TO WARMING TEMPERATURES AND
SLOWLY INCREASING LOW-LEVEL MOISTURE. RAIN CHANCES WILL REMAIN LOW
GIVEN THE LACK OF DEEP MOISTURE AND FORCING...MAINLY CONFINED TO
INLAND AREAS DURING AFTERNOON PEAK HEATING AS THE SEA BREEZE PUSHES
INLAND.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z SATURDAY.
EXTENDED AVIATION...VFR CONDITIONS SHOULD PREVAIL.
&&
.MARINE...
TODAY...A WEAK COLD FRONT WILL MOVE OFFSHORE THIS MORNING WITH
NORTHWEST WINDS PREVAILING ACROSS THE WATERS. WIND SPEEDS WILL
GENERALLY BE IN THE 10-15 KT RANGE WITH SEAS NO HIGHER THAN 2-4
FT DUE TO THE LIMITED OFFSHORE FETCH.
TONIGHT...A REINFORCING COLD FRONT WILL MOVE THROUGH EARLY THIS
EVENING...WITH A STRONG NORTHERLY SURGE DEVELOPING IN ITS WAKE.
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE OUTER GEORGIA
WATERS DUE TO THE ELEVATED WINDS/SEAS ASSOCIATED WITH THE
NORTHERLY SURGE. CONDITIONS WILL BE NEAR SMALL CRAFT ADVISORY
LEVELS WITHIN 20 NM OF THE COAST...ESPECIALLY IN GEORGIA...HOWEVER
CONFIDENCE IS TOO LOW GIVEN THE MARGINAL CONDITIONS TO ISSUE ANY
ADDITIONAL SMALL CRAFT ADVISORIES AT THIS TIME.
SATURDAY THROUGH WEDNESDAY...HIGH PRESSURE WILL MOVE OFFSHORE EARLY
NEXT WEEK AND PERSIST THROUGH MID WEEK. ENHANCED WINDS/SEAS EARLY
SATURDAY WILL DIMINISH DURING THE DAY AS THE HIGH GAINS MORE
INFLUENCE AND THE PRESSURE GRADIENT SLACKENS. A MORE TYPICAL
SPRINGTIME PATTERN WILL DOMINATE THERAFTER WITH SOME WIND
ENHANCEMENT DURING THE DAY NEAR THE COAST AS THE SEA BREEZE DEVELOPS
AND THEN OFFSHORE OVERNIGHT WITH NOCTURNAL SURGING.
HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS
THROUGH THE PERIOD.
RIP CURRENTS...THE COMBINATION OF ASTRONOMICAL INFLUENCES AND AN 8
SECOND LONG PERIOD SWELL WILL RESULT IN A MODERATE RISK OF RIP
CURRENTS AT AREA BEACHES TODAY. THE ENHANCED RIP CURRENT RISK MAY
PERSIST INTO SATURDAY.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE THIS EVENING AND AGAIN SATURDAY EVENING. BY THE TIME OF THE
HIGH TIDE SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE AS
ASTRONOMICAL FACTORS WILL CAUSE HIGHER THAN TYPICAL TIDES.
&&
.CLIMATE...
RECORD LOW TEMPERATURES FOR MAY 25TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....47 SET IN 1967
DOWNTOWN CHARLESTON /KCHL/..................54 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1967
RECORD LOW TEMPERATURES FOR MAY 26TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....50 SET IN 1979
DOWNTOWN CHARLESTON /KCHL/..................50 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1979
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT
SATURDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...JAQ/RJB
LONG TERM...RJB
AVIATION...JAQ/RJB
MARINE...JAQ/RJB
TIDES/COASTAL FLOODING...
CLIMATE...
000
FXUS62 KGSP 241125
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
725 AM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TODAY...BRINGING
COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL
MODERATE BY THE BEGINNING OF NEXT WEEK...WITH A CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM...STILL A FEW NW FLOW SHWRS ALONG THE TN BORDER...BUT
ON A DECREASING TREND. COLD AIR ADVECTION AND THE PASSAGE OF A
STRONG MID LVL SHORTWAVE IS FINALLY USHERING IN SOME BREEZY
CONDITIONS ALREADY IN THE MTNS...WITH THE FRENCH BROAD VALLEY IN A
FAVORABLE CHANNELED WIND DIRECTION THIS MORNING. STILL PLAN TO HOLD
OFF ANY WIND ADV ATTM...BUT TRENDS WILL BE WATCHED OVER NEXT COUPLE
HOURS.
AS OF 300 AM...CONDITIONS ARE GRADUALLY DRYING OUT BEHIND THE
PASSAGE OF A COLD FRONT EARLY THIS MORNING. THERE IS ENUF LLVL
MOISTURE IN THE NWLY FLOW FOR SCATTERED SHWRS TO DEVELOP AND AFFECT
THE UPSLOPE AREAS ALONG THE TN LINE. THIS ACTIVITY SHUD WANE BY MID
MORNING...AS UPPER SHORTWAVE TROF PASSES BY AND DRIER AIR WORKS IN.
TODAY...DRY HIGH PRES WILL BEGIN TO CONTINUE BUILD INTO THE AREA
FROM THE NW. MOST OF THE GUIDANCE...THE NAM IN PARTICULAR...INDICATE
BREEZY TO WINDY CONDITIONS ACRS THE CWFA. IN FACT...THE HIGH TERRAIN
AND SOME OF THE VALLEYS WHERE A GAP WIND WILL SET UP MAY APPROACH
WIND ADV CRITERIA...MAINLY DURING THE MORNING HOURS. CONFIDENCE NOT
HIGH ENUF TO GO WITH A WIND ADV IN THE MTNS. ELSEWHERE...BREEZY
CONDITIONS WARRANTS CAUTION ON AREA LAKES. TEMPS WILL BE BELOW
NORMAL UNDER SUNNY TO MOSTLY SUNNY SKIES.
TONIGHT...THE SFC HIGH WILL STILL BE CENTERED TO OUR NW...SO MIXING
IS EXPECTED TO CONTINUE THRU THE NIGHT. CLEAR SKIES AND CAA WILL
ALLOW TEMPS TO DROP INTO THE 30S IN THE MTNS AND 40S ACRS MOST OF
THE PIEDMONT. PATCHY FROST IS POSSIBLE IN THE SHELTERED
VALLEYS...BUT WIDESPREAD FROST IS NOT EXPECTED DUE TO THE MIXING
ACRS THE HIGH TERRAIN.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...GENERALLY FAIR WEATHER SATURDAY THROUGH SUNDAY
NIGHT. CLOUD COVER WILL INCREASE SATURDAY NIGHT...WITH VARIABLY
CLOUDY CONDITIONS EXPECTED INTO SUNDAY NIGHT. THIS WILL BE THE
RESULT OF WARM ADVECTION ON THE BACK SIDE OF A STRONG LONG WAVE
TROUGH. OVERALL THE FORCING LOOKS WEAK AND MOST OF WHAT WE SHOULD
SEE DURING THIS PERIOD WILL BE AC/SC AND PERHAPS A FEW AREAS OF
HIGH-BASED SPRINKLES OR LIGHT SHOWERS...PARTICULARLY SATURDAY NIGHT.
MAX TEMPS SATURDAY WILL BE A COUPLE CATEGORIES BELOW
NORMAL...REBOUNDING A FEW DEGREES ON SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE EXTENDED FORECAST LOOKS GOOD AND NO MAJOR
CHANGES HAVE BEEN MADE TO THE GRIDS. THE 00 UTC GFS AND YDAYS 12 UTC
ECMWF ARE IN GOOD AGREEMENT IN GRADUALLY BUILDING A LONG WAVE RIDGE
ACROSS THE LOWER MS RIVER VALLEY AND DEEP SOUTH STATES THROUGH THE
PERIOD. WE WILL START OUT THE PERIOD UNDER NW FLOW ON THE BACK SIDE
OF A LARGE LONG WAVE RIDGE CENTERED OVER THE WRN ATLANTIC. THE
MODELS HAVE QUITE A BIT OF MID AND UPPER LEVEL MOISTURE ON THE BACK
SIDE OF THE TROUGH...THE RESULT OF LOW AND MID LEVEL ISENTROPIC
UPGLIDE. STILL...THE SFC DEWPOINTS ARE LOW AND PCPN CHANCES MONDAY
SHOULD MAINLY BE CONFINED TO SPRINKLES OR LIGHT HIGH-BASED SHOWERS
OVER THE MTNS. TUE THROUGH THU BNDRY LAYER MOISTURE INCREASES AS THE
SFC RIDGE AXIS MOVES OFF THE COAST. THE GFS HAS THE BEST INSTABILITY
BY FAR OVER THE MOUNTAINS TUE AND WED...WITH A LITTLE MORE DRYING ON
FRI. AT THIS POINT LOW CHANCE POPS OVER THE MTNS AND SLIGHT CHANCE
POPS ELSEWHERE ALL THREE DAYS STILL LOOKS GOOD. I DID NUDGE TEMPS UP
A LITTLE TUE. I THINK WED AND THU ARE PROBABLY A LITTLE TOO
COOL...BUT I/LL LEAVE THAT FOR THE DAY SHIFT TO DECIDE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR WITH SOME LINGERING MID CLOUDS THRU ABOUT 14Z. A NW
WIND EXPECTED THRU THE PERIOD...INCREASING INTO THE 10-15 KT RANGE
BY MID MORNING...WITH GUSTS IN THE 20-25 KT RANGE EXPECTED THRU THE
AFTN. WINDS DIMINISH AROUND SUNSET THIS EVENING.
AT KAVL...STRONG CHANNELED VALLEY WINDS WILL CONTINUE THRU THE DAY.
GENERALLY SUSTAINED 15-20 KTS AND GUSTS POSSIBLY IN THE 30-35 KT
RANGE. SOME MOISTURE WILL CONTINUE TO WORK UP THE VALLEY THRU ABOUT
MID MORNING...WITH ANY CIGS EXPECTED TO BE VFR. HOWEVER...BRIEF
PERIODS OF MVFR CIGS ARE POSSIBLE. SO WILL HAVE TEMPO FOR A COUPLE
HOURS. WINDS WILL BEGIN TO DIMINISH AFTER SUNSET THIS EVENING.
ELSEWHERE...VFR CONDITIONS ARE EXPECTED AT ALL OTHER TAF SITES THRU
THE PERIOD. WINDS WILL BE THE MAIN CONCERN TODAY. EXPECTING ALL
SITES TO HAVE WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS
FROM LATE MORNING THRU THE AFTN.
OUTLOOK...WITH DRY HIGH PRES DOMINATING THE WEATHER ACRS THE REGION
THRU THE WEEKEND...NO SIGNIFICANT AVIATION CONCERNS ARE EXPECTED.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 92% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA TODAY. AFTERNOON MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS
TODAY. IF ANY LAND MANAGEMENT OFFICIALS THINK THAT A FIRE DANGER
STATEMENT IS WARRANTED PLEASE CONTACT OUR OFFICE.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...ARK
FIRE WEATHER...
000
FXUS62 KCAE 241046
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
645 AM EDT FRI MAY 24 2013
.SYNOPSIS...
THE PRESSURE RIDGE IN THE MISSISSIPPI RIVER VALLEY TODAY WILL MOVE
EASTWARD. THE RIDGE WILL BE ALONG THE EAST COAST SATURDAY NIGHT
AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FURTHER DRYING HAS OCCURRED BEHIND THE COLD FRONT. IT WILL BE A
DRY AND BREEZY DAY. WE ARE GETTING OFF TO A RELATIVELY WARM START
BECAUSE OF MIXING. USED THE WARMER TEMPERATURE GUIDANCE TODAY. THE
NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS WIND GUSTS AROUND 20
KNOTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE DRY PRESSURE RIDGE APPROACHING FROM THE WEST WILL DOMINATE
THROUGH SATURDAY NIGHT. BELOW NORMAL TEMPERATURES WILL BE
ASSOCIATED WITH THIS AIR MASS. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST. EXPECT LOWS IN THE 40S TONIGHT. SATURDAY
NIGHT SHOULD NOT BE QUITE AS COOL BECAUSE OF AIR MASS
MODIFICATION.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH AN UPPER RIDGE
WORKING INTO THE FORECAST AREA FROM THE WEST. THE GFS AND ECMWF
SHOW A WEAK SURFACE FRONTAL BOUNDARY WHICH REMAINS MAINLY TO THE
NORTH BUT THE ECMWF SHOWS THE FRONT A LITTLE STRONGER COMPARED TO
THE GFS. THE ECMWF ALSO DISPLAYS THE FRONT FARTHER TO THE SOUTH.
IT SHOULD BE DRY TO START SUNDAY AND MONDAY BUT BY THE END OF THE
PERIOD...MOISTURE AND INSTABILITY WILL INCREASE. EXPECT DIURNAL
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY WITH COVERAGE LIMITED BY
THE UPPER RIDGING. THE GFS ENSEMBLE MEANS SUPPORT JUST SLIGHT
CHANCE POPS.
&&
.AVIATION /11Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
DRIER AIR WILL FILTER IN BEHIND A WEAK SURFACE TROUGH EARLY THIS
MORNING. WILL MENTION LLWS UNTIL 14Z DUE WIND SPEEDS AROUND 30 KTS
AROUND 2000 FT AGL. BREEZY CONDITIONS EXPECTED BY LATE MORNING/EARLY
AFTERNOON...BEHIND A DRY COLD FRONT THAT WILL MOVE THROUGH LATER
THIS MORNING. WINDS WILL DIMINISH BY 00Z SATURDAY TO LESS THAN 10
KNOTS.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY THIS AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WIND APPEARS MARGINAL FOR A RED FLAG WARNING.
EXPECT GUSTS NEAR 25 MPH. FUEL MOISTURE IS HIGH REDUCING THE FIRE
THREAT.
&&
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES WILL OCCUR TONIGHT WITH LOWS IN
THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW FOR MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW FOR MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 241026
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
626 AM EDT FRI MAY 24 2013
.SYNOPSIS...
THE PRESSURE RIDGE IN THE MISSISSIPPI RIVER VALLEY TODAY WILL MOVE
EASTWARD. THE RIDGE WILL BE ALONG THE EAST COAST SATURDAY NIGHT
AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FURTHER DRYING HAS OCCURRED BEHIND THE COLD FRONT. IT WILL BE A
DRY AND BREEZY DAY. WE ARE GETTING OFF TO A RELATIVELY WARM START
BECAUSE OF MIXING. USED THE WARMER TEMPERATURE GUIDANCE TODAY. THE
NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS WIND GUSTS AROUND 20
KNOTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE DRY PRESSURE RIDGE APPROACHING FROM THE WEST WILL DOMINATE
THROUGH SATURDAY NIGHT. BELOW NORMAL TEMPERATURES WILL BE
ASSOCIATED WITH THIS AIR MASS. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST. EXPECT LOWS IN THE 40S TONIGHT. SATURDAY
NIGHT SHOULD NOT BE QUITE AS COOL BECAUSE OF AIR MASS
MODIFICATION.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH AN UPPER RIDGE
WORKING INTO THE FORECAST AREA FROM THE WEST. THE GFS AND ECMWF
SHOW A WEAK SURFACE FRONTAL BOUNDARY WHICH REMAINS MAINLY TO THE
NORTH BUT THE ECMWF SHOWS THE FRONT A LITTLE STRONGER COMPARED TO
THE GFS. THE ECMWF ALSO DISPLAYS THE FRONT FARTHER TO THE SOUTH.
IT SHOULD BE DRY TO START SUNDAY AND MONDAY BUT BY THE END OF THE
PERIOD...MOISTURE AND INSTABILITY WILL INCREASE. EXPECT DIURNAL
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY WITH COVERAGE LIMITED BY
THE UPPER RIDGING. THE GFS ENSEMBLE MEANS SUPPORT JUST SLIGHT
CHANCE POPS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
DRIER AIR WILL FILTER IN BEHIND A WEAK SURFACE FRONT EARLY THIS
MORNING. WILL MENTION LLWS UNTIL 14Z DUE WIND SPEEDS AROUND 30 KTS
AROUND 2000 FT AGL. BREEZY CONDITIONS EXPECTED BY LATE MORNING/EARLY
AFTERNOON...BEHIND A DRY COLD FRONT THAT WILL MOVE THROUGH LATER
THIS MORNING. WINDS WILL DIMINISH BY 00Z SATURDAY TO LESS THAN 10
KNOTS.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY THIS AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WIND APPEARS MARGINAL FOR A RED FLAG WARNING.
EXPECT GUSTS NEAR 25 MPH. FUEL MOISTURE IS HIGH REDUCING THE FIRE
THREAT.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES WILL OCCUR TONIGHT WITH LOWS IN
THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW FOR MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW FOR MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 240825
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
425 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE OFFSHORE THIS MORNING...FOLLOWED BY A
REINFORCING COLD FRONT LATE THIS AFTERNOON AND EARLY THIS EVENING.
HIGH PRESSURE WILL THEN BUILD INTO THE REGION THROUGH NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR IMAGERY EARLY THIS MORNING DEPICTS A BROAD UPPER LEVEL
TROUGH CENTERED OVER THE GREAT LAKES REGION. MEANWHILE AT THE
SURFACE...A COLD FRONT EXTENDS ACROSS THE UPSTATE OF SOUTH
CAROLINA AND NORTH-CENTRAL GEORGIA...WITH A WEAK PRE-FRONTAL
TROUGH SHIFTING TOWARD THE COAST.
AS THE DAY PROGRESSES...THE UPPER LEVEL TROUGH WILL DIG ACROSS
THE MID-ATLANTIC REGION. THIS WILL PUSH THE PRIMARY COLD FRONT
ACROSS THE AREA LATER THIS MORNING...WITH A REINFORCING COLD FRONT
THEN EXPECTED TO SHIFT INTO THE AREA LATE THIS AFTERNOON AS THE
TROUGH AXIS CROSSES.
THE PRE-FRONTAL TROUGH WAS RESPONSIBLE FOR SOME ISOLATED SHOWERS
ACROSS SOUTHEAST GEORGIA OVERNIGHT...BUT THIS ACTIVITY SHOULD END
AS THE TROUGH MOVES OFFSHORE PRIOR TO DAYBREAK. THE DRY WESTERLY
FLOW BEHIND THE PRE-FRONTAL TROUGH WILL PREVENT ANY ADDITIONAL
SHOWERS FROM FORMING AS THE PRIMARY COLD FRONT MOVES
THROUGH...WITH THE FLOW THEN VEERING NORTHWEST INTO THIS
AFTERNOON. THERE COULD BE SOME SCATTERED MID LEVEL CLOUDS BENEATH
THE UPPER TROUGH...ESPECIALLY OVER SOUTHEAST SOUTH CAROLINA...BUT
A GOOD AMOUNT OF SUNSHINE AND A STRONG DOWNSLOPE FLOW WILL SUPPORT
HIGHS IN THE MID TO UPPER 80S ACROSS THE AREA AWAY FROM THE
IMMEDIATE COAST. DEEP MIXING THIS AFTERNOON WILL SUPPORT BREEZY
CONDITIONS...WITH WINDS AS HIGH AS 15-20 MPH WITH GUSTS TO 25 MPH
AT TIMES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...THE UPPER LEVEL TROUGH WILL BEGIN TO SHIFT OFF THE MID-
ATLANTIC COAST THIS EVENING THEN PROGRESS OFFSHORE OVERNIGHT. A
REINFORCING COLD FRONT WILL COMPLETE ITS PASSAGE ACROSS THE AREA
DURING THE EARLY EVENING...WITH A NORTHERLY FLOW DEVELOPING IN ITS
WAKE AS HIGH PRESSURE BUILDS FROM THE GREAT LAKES REGION. THE
REINFORCING COLD FRONT WILL USHER IN A SIGNIFICANTLY DRIER AND
COOLER AIRMASS. THE COLD AIR ADVECTION WILL CAUSE TEMPERATURES TO
PLUMMET INTO THE UPPER 40S TO LOWER 50S AWAY FROM THE IMMEDIATE
COAST...WITH SOME MID 40S POSSIBLE WELL INLAND IF WINDS FULLY
DECOUPLE.
SATURDAY THROUGH MONDAY...MEDIUM RANGE GUIDANCE IS IN PRETTY GOOD
AGREEMENT THIS PERIOD SHOWING THE UPPER TROUGH SHIFTING OFFSHORE
WITH THE SURFACE HIGH TO FOLLOW. THIS WILL KEEP A DRY AND COOLER
THAN NORMAL AIR MASS IN PLACE. DEEP MOISTURE AND FORCING FOR
ASCENT WILL BE LACKING SO RAINFALL IS NOT EXPECTED THROUGH THE
PERIOD. THE BEST CHANCE OF ISOLATED SHOWERS WILL LIKELY COME
MONDAY AFTERNOON...MAINLY NORTH OF CHARLESTON...AS THE SEA BREEZE
PUSHES INLAND IN AN AXIS OF SLIGHTLY DEEPER MOISTURE.
WITH THE VERY DRY AIRMASS IN PLACE...TEMPERATURES WILL VARY ABOUT
25-30 DEGREES FROM THE MORNING LOWS TO THE AFTERNOON HIGHS. MORNING
LOWS SUNDAY COULD GET WITHIN A FEW DEGREES OF THE RECORDS AT
CHARLESTON AND SAVANNAH.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
DECENT MODEL AGREEMENT THIS PERIOD WITH ABOVE AVERAGE FORECAST
CONFIDENCE. UPPER HIGH PRESSURE SHOULD BUILD ACROSS THE REGION
TOWARD THE MIDDLE OF NEXT WEEK LEADING TO WARMING TEMPERATURES AND
SLOWLY INCREASING LOW-LEVEL MOISTURE. RAIN CHANCES WILL REMAIN LOW
GIVEN THE LACK OF DEEP MOISTURE AND FORCING...MAINLY CONFINED TO
INLAND AREAS DURING AFTERNOON PEAK HEATING AS THE SEA BREEZE PUSHES
INLAND.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 06Z SATURDAY.
EXTENDED AVIATION...VFR CONDITIONS SHOULD PREVAIL.
&&
.MARINE...
TODAY...A WEAK COLD FRONT WILL MOVE OFFSHORE THIS MORNING WITH
NORTHWEST WINDS PREVAILING ACROSS THE WATERS. WIND SPEEDS WILL
GENERALLY BE IN THE 10-15 KT RANGE TODAY...ALTHOUGH SOME HIGHER WINDS
COULD OCCUR OVER THE OUTER GEORGIA WATERS THIS MORNING. SEAS WILL
BE NO HIGHER THAN 2-4 FT WITH THE LIMITED OFFSHORE FETCH.
TONIGHT...A REINFORCING COLD FRONT WILL MOVE THROUGH EARLY THIS
EVENING...WITH A STRONG NORTHERLY SURGE DEVELOPING IN ITS WAKE.
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE OUTER GEORGIA
WATERS DUE TO THE ELEVATED WINDS/SEAS ASSOCIATED WITH THE
NORTHERLY SURGE. CONDITIONS WILL BE NEAR SMALL CRAFT ADVISORY
LEVELS WITHIN 20 NM OF THE COAST...ESPECIALLY IN GEORGIA...HOWEVER
CONFIDENCE IS TOO LOW GIVEN THE MARGINAL CONDITIONS TO ISSUE ANY
ADDITIONAL SMALL CRAFT ADVISORIES AT THIS TIME.
SATURDAY THROUGH WEDNESDAY...HIGH PRESSURE WILL MOVE OFFSHORE EARLY
NEXT WEEK AND PERSIST THROUGH MID WEEK. ENHANCED WINDS/SEAS EARLY
SATURDAY WILL DIMINISH DURING THE DAY AS THE HIGH GAINS MORE
INFLUENCE AND THE PRESSURE GRADIENT SLACKENS. A MORE TYPICAL
SPRINGTIME PATTERN WILL DOMINATE THERAFTER WITH SOME WIND
ENHANCEMENT DURING THE DAY NEAR THE COAST AS THE SEA BREEZE DEVELOPS
AND THEN OFFSHORE OVERNIGHT WITH NOCTURNAL SURGING.
HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS
THROUGH THE PERIOD.
RIP CURRENTS...THE COMBINATION OF ASTRONOMICAL INFLUENCES AND AN 8
SECOND LONG PERIOD SWELL WILL RESULT IN A MODERATE RISK OF RIP
CURRENTS AT AREA BEACHES TODAY. THE ENHANCED RIP CURRENT RISK MAY
PERSIST INTO SATURDAY.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE THIS EVENING AND AGAIN SATURDAY EVENING. BY THE TIME OF THE
HIGH TIDE SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE AS
ASTRONOMICAL FACTORS WILL CAUSE HIGHER THAN TYPICAL TIDES.
&&
.CLIMATE...
RECORD LOW TEMPERATURES FOR MAY 25TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....47 SET IN 1967
DOWNTOWN CHARLESTON /KCHL/..................54 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1967
RECORD LOW TEMPERATURES FOR MAY 26TH...
CHARLESTON INTERNATIONAL AIRPORT /KCHS/.....50 SET IN 1979
DOWNTOWN CHARLESTON /KCHL/..................50 SET IN 1979
SAVANNAH/HHI INTERNATIONAL AIRPORT /KSAV/...49 SET IN 1979
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT
SATURDAY FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...JAQ/RJB
LONG TERM...RJB
AVIATION...JAQ/RJB
MARINE...JAQ/RJB
TIDES/COASTAL FLOODING...JAQ/RJB
CLIMATE...JAQ
000
FXUS62 KGSP 240751
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
351 AM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TODAY...BRINGING
COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES WILL
MODERATE BY THE BEGINNING OF NEXT WEEK...WITH A CHANCE OF AFTERNOON
SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM...CONDITIONS ARE GRADUALLY DRYING OUT BEHIND THE
PASSAGE OF A COLD FRONT EARLY THIS MORNING. THERE IS ENUF LLVL
MOISTURE IN THE NWLY FLOW FOR SCATTERED SHWRS TO DEVELOP AND AFFECT
THE UPSLOPE AREAS ALONG THE TN LINE. THIS ACTIVITY SHUD WANE BY MID
MORNING...AS UPPER SHORTWAVE TROF PASSES BY AND DRIER AIR WORKS IN.
TODAY...DRY HIGH PRES WILL BEGIN TO CONTINUE BUILD INTO THE AREA
FROM THE NW. MOST OF THE GUIDANCE...THE NAM IN PARTICULAR...INDICATE
BREEZY TO WINDY CONDITIONS ACRS THE CWFA. IN FACT...THE HIGH TERRAIN
AND SOME OF THE VALLEYS WHERE A GAP WIND WILL SET UP MAY APPROACH
WIND ADV CRITERIA...MAINLY DURING THE MORNING HOURS. CONFIDENCE NOT
HIGH ENUF TO GO WITH A WIND ADV IN THE MTNS. ELSEWHERE...BREEZY
CONDITIONS WARRANTS CAUTION ON AREA LAKES. TEMPS WILL BE BELOW
NORMAL UNDER SUNNY TO MOSTLY SUNNY SKIES.
TONIGHT...THE SFC HIGH WILL STILL BE CENTERED TO OUR NW...SO MIXING
IS EXPECTED TO CONTINUE THRU THE NIGHT. CLEAR SKIES AND CAA WILL
ALLOW TEMPS TO DROP INTO THE 30S IN THE MTNS AND 40S ACRS MOST OF
THE PIEDMONT. PATCHY FROST IS POSSIBLE IN THE SHELTERED
VALLEYS...BUT WIDESPREAD FROST IS NOT EXPECTED DUE TO THE MIXING
ACRS THE HIGH TERRAIN.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...GENERALLY FAIR WEATHER SATURDAY THROUGH SUNDAY
NIGHT. CLOUD COVER WILL INCREASE SATURDAY NIGHT...WITH VARIABLY
CLOUDY CONDITIONS EXPECTED INTO SUNDAY NIGHT. THIS WILL BE THE
RESULT OF WARM ADVECTION ON THE BACK SIDE OF A STRONG LONG WAVE
TROUGH. OVERALL THE FORCING LOOKS WEAK AND MOST OF WHAT WE SHOULD
SEE DURING THIS PERIOD WILL BE AC/SC AND PERHAPS A FEW AREAS OF
HIGH-BASED SPRINKLES OR LIGHT SHOWERS...PARTICULARLY SATURDAY NIGHT.
MAX TEMPS SATURDAY WILL BE A COUPLE CATEGORIES BELOW
NORMAL...REBOUNDING A FEW DEGREES ON SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE EXTENDED FORECAST LOOKS GOOD AND NO MAJOR
CHANGES HAVE BEEN MADE TO THE GRIDS. THE 00 UTC GFS AND YDAYS 12 UTC
ECMWF ARE IN GOOD AGREEMENT IN GRADUALLY BUILDING A LONG WAVE RIDGE
ACROSS THE LOWER MS RIVER VALLEY AND DEEP SOUTH STATES THROUGH THE
PERIOD. WE WILL START OUT THE PERIOD UNDER NW FLOW ON THE BACK SIDE
OF A LARGE LONG WAVE RIDGE CENTERED OVER THE WRN ATLANTIC. THE
MODELS HAVE QUITE A BIT OF MID AND UPPER LEVEL MOISTURE ON THE BACK
SIDE OF THE TROUGH...THE RESULT OF LOW AND MID LEVEL ISENTROPIC
UPGLIDE. STILL...THE SFC DEWPOINTS ARE LOW AND PCPN CHANCES MONDAY
SHOULD MAINLY BE CONFINED TO SPRINKLES OR LIGHT HIGH-BASED SHOWERS
OVER THE MTNS. TUE THROUGH THU BNDRY LAYER MOISTURE INCREASES AS THE
SFC RIDGE AXIS MOVES OFF THE COAST. THE GFS HAS THE BEST INSTABILITY
BY FAR OVER THE MOUNTAINS TUE AND WED...WITH A LITTLE MORE DRYING ON
FRI. AT THIS POINT LOW CHANCE POPS OVER THE MTNS AND SLIGHT CHANCE
POPS ELSEWHERE ALL THREE DAYS STILL LOOKS GOOD. I DID NUDGE TEMPS UP
A LITTLE TUE. I THINK WED AND THU ARE PROBABLY A LITTLE TOO
COOL...BUT I/LL LEAVE THAT FOR THE DAY SHIFT TO DECIDE.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR WITH SOME LINGERING MID CLOUDS FOR THE FIRST FEW HOURS
OF THE 06Z TAF. A NNW WIND EXPECTED THRU THE PERIOD...INCREASING
INTO THE 10-15 KT RANGE BY MID MORNING...WITH GUSTS IN THE 20-25 KT
RANGE EXPECTED THRU THE AFTN. WINDS DIMINISH AROUND SUNSET THIS
EVENING.
AT KAVL...STRONG GAP WINDS EXPECTED TO PICK UP BEFORE DAYBREAK...AND
CONTINUE THRU THE DAY. GENERALLY SUSTAINED 15-20 KTS AND GUSTS
POSSIBLY IN THE 30-35 KT RANGE. SOME MOISTURE WILL CONTINUE TO WORK
UP THE VALLEY THRU ABOUT MID MORNING...WITH ANY CIGS EXPECTED TO BE
VFR. HOWEVER...A BRIEF PERIOD OF MVFR CIG CANNOT BE RULED OUT...MOST
LIKELY RIGHT BEFORE OR DURING DAYBREAK. WINDS WILL BEGIN TO DIMINISH
AFTER SUNSET THIS EVENING.
ELSEWHERE...VFR CONDITIONS ARE EXPECTED AT ALL OTHER TAF SITES
THROUGH THE PERIOD...WITH MID CLOUDS EVENTUALLY CLEARING OUT BY
DAYBREAK. WINDS WILL BE THE MAIN CONCERN TODAY. EXPECTING ALL SITES
TO HAVE WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS FROM
LATE MORNING THRU THE AFTN.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 82% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.FIRE WEATHER...
IT WILL BE WINDY OVER THE MOUNTAINS AND BREEZY OVER MUCH OF THE REST
OF THE FORECAST AREA TODAY. AFTERNOON MINIMUM RELATIVE HUMIDITY
VALUES WILL FALL TO BETWEEN 25 AND 30 PERCENT. WITH RECENT
WIDESPREAD RAINFALL...FUEL MOISTURE VALUES ARE GENERALLY STILL
HIGH...AND WE DO NOT ANTICIPATE NEEDING ANY FIRE DANGER PRODUCTS
TODAY. IF ANY LAND MANAGEMENT OFFICIALS THINK THAT A FIRE DANGER
STATEMENT IS WARRANTED PLEASE CONTACT OUR OFFICE.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...ARK
FIRE WEATHER...MCAVOY
000
FXUS62 KCAE 240722
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
322 AM EDT FRI MAY 24 2013
.SYNOPSIS...
THE PRESSURE RIDGE IN THE MISSISSIPPI RIVER VALLEY TODAY WILL MOVE
EASTWARD. THE RIDGE WILL BE ALONG THE EAST COAST SATURDAY NIGHT
AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FURTHER DRYING HAS OCCURRED BEHIND THE COLD FRONT. IT WILL BE A
DRY AND BREEZY DAY. WE ARE GETTING OFF TO A RELATIVELY WARM START
BECAUSE OF MIXING. USED THE WARMER TEMPERATURE GUIDANCE TODAY. THE
NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS WIND GUSTS AROUND 20
KNOTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE DRY PRESSURE RIDGE APPROACHING FROM THE WEST WILL DOMINATE
THROUGH SATURDAY NIGHT. BELOW NORMAL TEMPERATURES WILL BE
ASSOCIATED WITH THIS AIR MASS. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST. EXPECT LOWS IN THE 40S TONIGHT. SATURDAY
NIGHT SHOULD NOT BE QUITE AS COOL BECAUSE OF AIR MASS
MODIFICATION.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH AN UPPER RIDGE
WORKING INTO THE FORECAST AREA FROM THE WEST. THE GFS AND ECMWF
SHOW A WEAK SURFACE FRONTAL BOUNDARY WHICH REMAINS MAINLY TO THE
NORTH BUT THE ECMWF SHOWS THE FRONT A LITTLE STRONGER COMPARED TO
THE GFS. THE ECMWF ALSO DISPLAYS THE FRONT FARTHER TO THE SOUTH.
IT SHOULD BE DRY TO START SUNDAY AND MONDAY BUT BY THE END OF THE
PERIOD...MOISTURE AND INSTABILITY WILL INCREASE. EXPECT DIURNAL
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY WITH COVERAGE LIMITED BY
THE UPPER RIDGING. THE GFS ENSEMBLE MEANS SUPPORT JUST SLIGHT
CHANCE POPS.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
SURFACE AND/OR BOUNDARY LAYER WINDS ARE EXPECTED TO STAY UP SOME
DURING THE EARLY MORNING HOURS...PLUS SOME DRIER AIR WILL
FILTER IN BEHIND A WEAK SURFACE TROUGH...THUS PRECLUDING ANY
FOG/STRATUS THREAT. WILL MENTION LLWS UNTIL 14Z DUE WIND SPEEDS
AROUND 35 KTS NEAR 2000 FT AGL. BREEZY CONDITIONS EXPECTED BY LATE
MORNING/EARLY AFTERNOON...BEHIND A DRY COLD FRONT THAT HAS MOVED THROUGH
THE AREA.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY THIS AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WIND APPEARS MARGINAL FOR A RED FLAG WARNING.
EXPECT GUSTS NEAR 25 MPH. FUEL MOISTURE IS HIGH REDUCING THE FIRE
THREAT.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES WILL OCCUR TONIGHT WITH LOWS IN
THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW FOR MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW FOR MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 240550
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
150 AM EDT FRI MAY 24 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1020 PM...CURRENT RADAR ANALYSIS PLACES A LINE OF CONVECTION
EXTENDING IN A NORTH/SOUTH ORIENTATION ACROSS THE SRN NORTH CAROLINA
PIEDMONT...TO INCLUDE CHARLOTTE METRO. THIS CONVECTION WILL
CONTINUE TO MOVE EASTWARD ACROSS CENTRAL NORTH CAROLINA BEFORE
EVENTUALLY DISSIPATING DUE TO LACK OF SURFACE ENERGY.
THUS...SLIGHTLY PULLED BACK POPS FURTHER ACROSS THE PIEDMONT TO END
SLIGHT CHANCE POPS A LITTLE SOONER THAN PREVIOUS FCST. WINDS STILL
LOOK TO BE SOMEWHAT GUSTY DURING THE DAY TOMORROW ACROSS THE ENTIRE
REGION AS SFC PRESSURE GRADIENT TIGHTENS. THUS FOR FRIDAY EXPECTING
SUSTAINED NNW WINDS NEARING 15-20KTS ACROSS THE HIGHER TERRAIN...AND
12-15KTS ELSEWHERE. LOOK FOR GUSTS IN THE MOUNTAINS TO REACH
25-30KTS AND AROUND 15-20KTS IN THE LOWER ELEVATIONS. THEREFORE NOT
FCST TO REACH WIND ADVISORY CRITERIA AT THIS TIME. FCST LOOKS TO BE
ON TRACK AND NO CHANGES WERE MADE.
REMAINDER OF PREVIOUS DISCUSSION...
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AT KCLT...VFR WITH SOME LINGERING MID CLOUDS FOR THE FIRST FEW HOURS
OF THE 06Z TAF. A NNW WIND EXPECTED THRU THE PERIOD...INCREASING
INTO THE 10-15 KT RANGE BY MID MORNING...WITH GUSTS IN THE 20-25 KT
RANGE EXPECTED THRU THE AFTN. WINDS DIMINISH AROUND SUNSET THIS
EVENING.
AT KAVL...STRONG GAP WINDS EXPECTED TO PICK UP BEFORE DAYBREAK...AND
CONTINUE THRU THE DAY. GENERALLY SUSTAINED 15-20 KTS AND GUSTS
POSSIBLY IN THE 30-35 KT RANGE. SOME MOISTURE WILL CONTINUE TO WORK
UP THE VALLEY THRU ABOUT MID MORNING...WITH ANY CIGS EXPECTED TO BE
VFR. HOWEVER...A BRIEF PERIOD OF MVFR CIG CANNOT BE RULED OUT...MOST
LIKELY RIGHT BEFORE OR DURING DAYBREAK. WINDS WILL BEGIN TO DIMINISH
AFTER SUNSET THIS EVENING.
ELSEWHERE...VFR CONDITIONS ARE EXPECTED AT ALL OTHER TAF SITES
THROUGH THE PERIOD...WITH MID CLOUDS EVENTUALLY CLEARING OUT BY
DAYBREAK. WINDS WILL BE THE MAIN CONCERN TODAY. EXPECTING ALL SITES
TO HAVE WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS FROM
LATE MORNING THRU THE AFTN.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 84% HIGH 97% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...CDG/PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...ARK
000
FXUS62 KCAE 240538
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
138 AM EDT FRI MAY 24 2013
.SYNOPSIS...
THE PRESSURE RIDGE IN THE MISSISSIPPI RIVER VALLEY TODAY WILL MOVE
EASTWARD. THE RIDGE WILL BE ALONG THE EAST COAST SATURDAY NIGHT
AND SUNDAY.
&&
.NEAR TERM /THROUGH TODAY/...
FURTHER DRYING HAS OCCURRED BEHIND THE COLD FRONT. IT WILL BE A
DRY AND BREEZY DAY. WE ARE GETTING OFF TO A RELATIVELY WARM START
BECAUSE OF MIXING. USED THE WARMER TEMPERATURE GUIDANCE TODAY. THE
NAM BUFKIT MOMENTUM TRANSFER TOOL SUPPORTS WIND GUSTS AROUND 20
KNOTS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THE DRY PRESSURE RIDGE APPROACHING FROM THE WEST WILL DOMINATE
THROUGH SATURDAY NIGHT. BELOW NORMAL TEMPERATURES WILL BE
ASSOCIATED WITH THIS AIR MASS. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST. EXPECT LOWS IN THE 40S TONIGHT. SATURDAY
NIGHT SHOULD NOT BE QUITE AS COOL BECAUSE OF AIR MASS
MODIFICATION.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH AN UPPER RIDGE
WORKING INTO THE FORECAST AREA FROM THE WEST. THE GFS AND ECMWF
SHOW A WEAK SURFACE FRONTAL BOUNDARY WHICH REMAINS MAINLY TO THE
NORTH BUT THE ECMWF SHOWS THE FRONT A LITTLE STRONGER COMPARED TO
THE GFS. THE ECMWF ALSO DISPLAYS THE FRONT FARTHER TO THE SOUTH.
IT SHOULD BE DRY TO START SUNDAY AND MONDAY BUT BY THE END OF THE
PERIOD...MOISTURE AND INSTABILITY WILL INCREASE. EXPECT DIURNAL
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY WITH COVERAGE LIMITED BY
THE UPPER RIDGING. THE GFS ENSEMBLE MEANS SUPPORT JUST SLIGHT
CHANCE POPS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
SURFACE AND/OR BOUNDARY LAYER WINDS ARE EXPECTED TO STAY UP SOME
DURING THE EARLY MORNING HOURS...PLUS SOME DRIER AIR WILL
FILTER IN BEHIND A WEAK SURFACE TROUGH...THUS PRECLUDING ANY
FOG/STRATUS THREAT. WILL MENTION LLWS UNTIL 14Z DUE WIND SPEEDS
AROUND 35 KTS NEAR 2000 FT AGL. BREEZY CONDITIONS EXPECTED BY LATE
MORNING/EARLY AFTERNOON...BEHIND A DRY COLD FRONT THAT HAS MOVED THROUGH
THE AREA.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION EXPECTED.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY THIS AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WINDS APPEAR MARGINAL FOR A RED FLAG
WARNING. EXPECT GUSTS NEAR 25 MPH. FUEL MOISTURE IS HIGH REDUCING
THE FIRE THREAT.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES WILL OCCUR TONIGHT WITH LOWS IN
THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW FOR MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW FOR MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 240524
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
124 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION LATE TONIGHT...WITH DRY
HIGH PRESSURE BUILDING IN THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
IN GENERAL DRIER AIR WILL GRADUALLY FILTER INTO THE REGION
OVERNIGHT AS A WEAK FRONT MOVES THROUGH AND WINDS VEER NORTHWEST.
OVERALL..EXPECT MOSTLY CLEAR SKIES TO PREVAIL.
PATCHY FOG COULD DEVELOP ACROSS INLAND/NORTHERN COUNTIES DUE TO
EARLIER RAINFALL AND LIGHT WINDS.
OTHERWISE...MOST FORECAST PARAMETERS REMAIN IN DECENT SHAPE AND
REQUIRED ONLY MINOR/HOURLY AMENDMENTS OVERNIGHT. LOW TEMPERATURES
BY DAYBREAK WILL AVERAGE IN THE MID 60S AT MANY LOCATIONS...EXCEPT
IN THE LOWER 60S AT A FEW OF THE COOLEST INLAND SPOTS AND IN THE
LOWER 70S ON SOME BEACHES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
THE WEATHER WILL BE RELATIVELY QUIET DURING THIS PERIOD AS HIGH
PRESSURE BUILDS IN FROM THE NORTH ON FRIDAY...SETTLING OVER THE AREA
FOR THE WEEKEND. FRIDAY WILL BE THE WARMEST OF THE THREE DAYS AS
NORTHWESTERLY DOWNSLOPE FLOW WILL ALLOW FOR A LITTLE COMPRESSIONAL
HEATING AT LOW LEVELS. AFTERNOON MAX TEMPS WILL MANAGE TO GET TO
NEAR NORMAL UNDER MOSTLY SUNNY SKIES. THE WINDS MAY GET A BIT BREEZY
DURING THE LATE MORNING AND EARLY AFTERNOON HOURS WITH GOOD MIXING
IN THE BOUNDARY LAYER ALLOWING SOMEWHAT STRONGER WINDS TO MIX TO THE
SURFACE.
FRIDAY NIGHT...STRONG COOL ADVECTION SETTLES IN...WITH TEMPERATURES
DROPPING ALL NIGHT. RISING HEIGHTS ALOFT WILL HELP PROMOTE LOW LEVEL
SUBSIDENCE...KEEPING SKIES CLEAR. TEMPS WILL DROP INTO THE UPPER 40S
TO NEAR 50 WEST OF INTERSTATE 95...WITH LOWER 50S ELSEWHERE. A
PERSISTENT 5 TO 10 KNOT WIND WILL KEEP TEMPS FROM DROPPING EVEN
LOWER.
SATURDAY WILL BE COOL AND SUNNY AS A BUBBLE AREA OF HIGH PRESSURE
SETS UP IN THE NEIGHBORHOOD. DEW POINTS WILL DROP INTO THE 30S BY
AFTERNOON AWAY FROM THE COAST...WHICH IS VERY LOW FOR MEMORIAL DAY
WEEKEND. RELATIVE HUMIDITY VALUES BY THEMSELVES WOULD BE LOW
ENOUGH FOR FIRE WEATHER CONCERNS...BUT THE WINDS WILL BE GENERALLY
LESS THAN 10 KNOTS.
NOT MUCH CHANGE EXPECTED ON SUNDAY WITH THE HIGH REMAINING CLOSE BY.
A WEAK LEE TROF MAY DEVELOP BY AFTERNOON IN THE MIDLANDS...ALLOWING
FOR A BIT MORE ROBUST SEA BREEZE TO FORM...BUT THE LACK OF LOW LEVEL
MOISTURE WILL PREVENT ANY CONVECTIVE ACTIVITY. THERE COULD BE A
LITTLE MORE IN THE WAY OF CIRRUS AS A WEAK DISTURBANCE ALOFT ROTATES
AROUND THE DEEP UPPER LOW EXPECTED OVER NEW ENGLAND...BUT IT WONT
SIGNIFICANTLY DENT THE AMOUNT OF SUNSHINE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE REGION WILL BE SANDWICHED BETWEEN TWO AREAS OF HIGH PRESSURE
EARLY IN THE WEEK...THE STRONGER OF THE TWO PASSING ACROSS THE
MID-ATLANTIC REGION AND THE OTHER OVER THE NORTHEAST GULF OF
MEXICO. DEEPENING MOISTURE WILL RESULT IN AT LEAST AN INCREASE IN
CLOUD COVER...BUT IT APPEARS THE RAIN-FREE CONDITIONS SHOULD
PERSIST THROUGH MEMORIAL DAY. ATLANTIC HIGH PRESSURE WILL THEN
BECOME ESTABLISHED THROUGH THE MIDDLE OF NEXT WEEK...SUPPORTING
MAINLY DIURNAL ISOLATED CONVECTION EACH AFTERNOON ALONG AND AHEAD
OF THE SEA BREEZE TUESDAY THROUGH THURSDAY. TEMPERATURES WILL
MODERATE TO NEAR NORMAL BY EARLY NEXT WEEK AND CONTINUE NEAR
SEASONAL NORMS THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 06Z SATURDAY.
EXTENDED AVIATION...VFR CONDITIONS SHOULD PREVAIL.
&&
.MARINE...
WINDS WILL CONTINUE TO VEER TOWARD THE WEST AND WILL INCREASE IN
SPEED OVERNIGHT. WINDS AS HIGH AS 15-20 KT COULD DEVELOP ACROSS
WATERS BEYOND 20 NM LATE. SEAS WILL RANGE FROM 2-4FT WITHIN
NEARSHORE WATERS TO 3-5 FT BEYOND 20 NM. OFFSHORE WINDS WILL
CONTINUE FRIDAY...WITH WINDS VEERING TOWARD THE NORTHWEST
ESPECIALLY IN THE AFTERNOON.
THE MAIN PERIOD OF CONCERN WILL BE FRIDAY NIGHT BEHIND THE COLD
FRONT AS WINDS ACCELERATE FROM THE NORTH AND EVENTUALLY NORTH
NORTHEAST. WINDS AND SEAS WILL BE RIGHT AROUND SCA CRITERIA
OFFSHORE...BUT TOO MARGINAL TO ISSUE ANY HEADLINES AT THIS TIME.
WINDS AND SEAS WILL QUICKLY COME BACK DOWN SATURDAY AS THE
PRESSURE GRADIENT COLLAPSES WHILE HIGH PRESSURES SETTLES OVER THE
WATERS.
WINDS WILL BECOME DIURNALLY DRIVEN NEXT WEEK AS THE SURFACE
HIGH MOVES INTO THE ATLANTIC WITH A WEAK RIDGE STRETCHING WESTWARD
OVER THE CWA. SPEEDS SHOULD BE 15 KNOTS OR LESS THE FIRST HALF OF
NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENINGS. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE AS
ASTRONOMICAL FACTORS WILL CAUSE HIGHER THAN TYPICAL TIDES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...JAQ
MARINE...SPR/FWA
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 240329
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1129 PM EDT THU MAY 23 2013
.SYNOPSIS...
FURTHER DRYING WILL OCCUR BEHIND THE COLD FRONT TONIGHT. THE
PRESSURE RIDGE BEHIND THE FRONT WILL EXTEND THROUGH THE
MISSISSIPPI RIVER VALLEY FRIDAY. THE RIDGE WILL MOVE EASTWARD
AND BE ALONG THE EAST COAST SATURDAY NIGHT AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THE COLD FRONT WILL MOVE THROUGH THE FORECAST AREA OVERNIGHT.
LITTLE MOISTURE IS ASSOCIATED WITH THE FRONT. FURTHER DRYING
WILL OCCUR BEHIND THE FRONT BY MORNING. THE TEMPERATURE FORECAST
APPEARS ON TRACK WITH LOWS IN THE UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /6 AM FRIDAY THROUGH SATURDAY NIGHT/...
THE DRY PRESSURE RIDGE APPROACHING FROM THE WEST WILL DOMINATE
THROUGH SATURDAY NIGHT. BELOW NORMAL TEMPERATURES WILL BE
ASSOCIATED WITH THIS AIR MASS. EXPECT LOWS IN THE 40S FRIDAY
NIGHT. SATURDAY NIGHT SHOULD NOT BE QUITE AS COOL BECAUSE OF AIR
MASS MODIFICATION.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH UPPER RIDGE WORKING
IN FROM THE WEST. BOTH MODELS SHOW A WEAK SURFACE FRONTAL BOUNDARY
WHICH REMAINS MAINLY TO THE NORTH BUT ECMWF SHOWS THE FRONT A
LITTLE BIT STRONGER THAN THE GFS. THE ECMWF ALSO KEEPS THE FRONT
A LITTLE FARTHER TO THE SOUTH. DRY TO START SUNDAY AND MONDAY BUT
BY THE END OF THE PERIOD...MOISTURE AND INSTABILITY INCREASES.
EXPECT MORE DIURNAL SHOWERS AND THUNDERSTORMS TUESDAY THROUGH
WEDNESDAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
SURFACE AND/OR BOUNDARY LAYER WINDS ARE EXPECTED TO STAY UP SOME
LATE TONIGHT...PLUS SOME DRIER AIR WILL FILTER IN BEHIND A WEAK
SURFACE TROUGH...THUS PRECLUDING ANY FOG/STRATUS THREAT. BREEZY
CONDITIONS EXPECTED FRIDAY...BEHIND A DRY COLD FRONT THAT WILL COME
THROUGH IN THE MORNING.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY FRIDAY AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WINDS APPEAR MARGINAL FOR A RED FLAG WARNING...EXPECT
SUSTAINED WINDS MAINLY BELOW 20 MPH. WIND GUSTS EXPECTED TO AROUND
25 MPH. FUEL MOISTURE IS HIGH REDUCING THE FIRE THREAT.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES FRIDAY NIGHT/SATURDAY MORNING WITH
LOWS IN THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 240225
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1025 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 1020 PM...CURRENT RADAR ANALYSIS PLACES A LINE OF CONVECTION
EXTENDING IN A NORTH/SOUTH ORIENTATION ACROSS THE SRN NORTH CAROLINA
PIEDMONT...TO INCLUDE CHARLOTTE METRO. THIS CONVECTION WILL
CONTINUE TO MOVE EASTWARD ACROSS CENTRAL NORTH CAROLINA BEFORE
EVENTUALLY DISSIPATING DUE TO LACK OF SURFACE ENERGY.
THUS...SLIGHTLY PULLED BACK POPS FURTHER ACROSS THE PIEDMONT TO END
SLIGHT CHANCE POPS A LITTLE SOONER THAN PREVIOUS FCST. WINDS STILL
LOOK TO BE SOMEWHAT GUSTY DURING THE DAY TOMORROW ACROSS THE ENTIRE
REGION AS SFC PRESSURE GRADIENT TIGHTENS. THUS FOR FRIDAY EXPECTING
SUSTAINED NNW WINDS NEARING 15-20KTS ACROSS THE HIGHER TERRAIN...AND
12-15KTS ELSEWHERE. LOOK FOR GUSTS IN THE MOUNTAINS TO REACH
25-30KTS AND AROUND 15-20KTS IN THE LOWER ELEVATIONS. THEREFORE NOT
FCST TO REACH WIND ADVISORY CRITERIA AT THIS TIME. FCST LOOKS TO BE
ON TRACK AND NO CHANGES WERE MADE.
REMAINDER OF PREVIOUS DISCUSSION...
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
AT KCLT...EXPECTING VFR CONDITIONS TO PREVAIL THROUGH THE ENTIRE TAF
PERIOD. LOOKS AS IF THERE MIGHT BE ENOUGH CONVECTIVE DEBRIS IN THE
REGION TO KEEP CIGS AT AROUND THE 12-15KFT LEVEL THROUGH MOST OF THE
EVENING BEFORE SCATTERING OUT BY DAYBREAK. WINDS WILL SHIFT TO A
MORE NNW COMPONENT AROUND THE 04Z TIMEFRAME AND SHOULD STAY AROUND
6-7KTS GENERALLY. OTHERWISE...WINDS WILL INCREASE AROUND 14Z FRIDAY
MORNING AS SFC PRESSURE GRADIENT TIGHTENS AND LOW LEVEL WINDS MIX
DOWN. THUS...WENT WITH PREVAILING 12KTS WITH 25KT GUSTS FOR THE
REMAINDER OF THE TAF PERIOD.
ELSEWHERE...VFR CONDITIONS CAN BE EXPECTED AT ALL TAF SITES THROUGH
THE PERIOD AND CIGS WILL IMPROVE THROUGHOUT THE EVENING. AS
WITH KCLT ABOVE...WINDS WILL BE THE GREATEST CONCERN ON FRIDAY AS
850MB FLOW ALOFT MIXES DOWN. THUS...ALL SITES HAVE GROUPS WITH
PREVAILING WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS.
KAVL LOOKS TO HAVE THE HIGHEST WIND POTENTIAL AS FLOW CHANNELS
THROUGH THE FRENCH BROAD VALLEY AND IS EXPECT TO GUST NEAR 30KTS.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 91% HIGH 85% HIGH 98% HIGH 100%
KHKY HIGH 100% HIGH 95% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...CDG/PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...CDG
000
FXUS62 KCHS 240220
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1020 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION LATE TONIGHT...WITH DRY
HIGH PRESSURE BUILDING IN THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
DEEP LAYER TROUGHING AND ASSOCIATED/LOCALIZED LOW LEVEL CONVERGENCE
COULD SUPPORT ANOTHER SHOWER/THUNDERSTORM OR TWO ACROSS NORTHERN
COUNTIES AND ADJACENT COASTAL WATERS FOR A FEW MORE HOURS.
HOWEVER...IN GENERAL DRIER AIR WILL GRADUALLY FILTER INTO THE
REGION OVERNIGHT...ACCOMPANIED BY CLEAR/PARTLY CLOUDY SKIES.
PATCHY FOG COULD DEVELOP ACROSS INLAND/NORTHERN COUNTIES DUE TO
EARLIER RAINFALL AND LIGHT WINDS.
OTHERWISE...MOST FORECAST PARAMETERS REMAIN IN DECENT SHAPE AND
REQUIRED ONLY MINOR/HOURLY AMENDMENTS OVERNIGHT. LOW TEMPERATURES
BY DAYBREAK WILL AVERAGE IN THE MID 60S AT MANY LOCATIONS...EXCEPT
IN THE LOWER 60S AT A FEW OF THE COOLEST INLAND SPOTS AND IN THE
LOWER 70S ON SOME BEACHES.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
THE WEATHER WILL BE RELATIVELY QUIET DURING THIS PERIOD AS HIGH
PRESSURE BUILDS IN FROM THE NORTH ON FRIDAY...SETTLING OVER THE AREA
FOR THE WEEKEND. FRIDAY WILL BE THE WARMEST OF THE THREE DAYS AS
NORTHWESTERLY DOWNSLOPE FLOW WILL ALLOW FOR A LITTLE COMPRESSIONAL
HEATING AT LOW LEVELS. AFTERNOON MAX TEMPS WILL MANAGE TO GET TO
NEAR NORMAL UNDER MOSTLY SUNNY SKIES. THE WINDS MAY GET A BIT BREEZY
DURING THE LATE MORNING AND EARLY AFTERNOON HOURS WITH GOOD MIXING
IN THE BOUNDARY LAYER ALLOWING SOMEWHAT STRONGER WINDS TO MIX TO THE
SURFACE.
FRIDAY NIGHT...STRONG COOL ADVECTION SETTLES IN...WITH TEMPERATURES
DROPPING ALL NIGHT. RISING HEIGHTS ALOFT WILL HELP PROMOTE LOW LEVEL
SUBSIDENCE...KEEPING SKIES CLEAR. TEMPS WILL DROP INTO THE UPPER 40S
TO NEAR 50 WEST OF INTERSTATE 95...WITH LOWER 50S ELSEWHERE. A
PERSISTENT 5 TO 10 KNOT WIND WILL KEEP TEMPS FROM DROPPING EVEN
LOWER.
SATURDAY WILL BE COOL AND SUNNY AS A BUBBLE AREA OF HIGH PRESSURE
SETS UP IN THE NEIGHBORHOOD. DEW POINTS WILL DROP INTO THE 30S BY
AFTERNOON AWAY FROM THE COAST...WHICH IS VERY LOW FOR MEMORIAL DAY
WEEKEND. RELATIVE HUMIDITY VALUES BY THEMSELVES WOULD BE LOW
ENOUGH FOR FIRE WEATHER CONCERNS...BUT THE WINDS WILL BE GENERALLY
LESS THAN 10 KNOTS.
NOT MUCH CHANGE EXPECTED ON SUNDAY WITH THE HIGH REMAINING CLOSE BY.
A WEAK LEE TROF MAY DEVELOP BY AFTERNOON IN THE MIDLANDS...ALLOWING
FOR A BIT MORE ROBUST SEA BREEZE TO FORM...BUT THE LACK OF LOW LEVEL
MOISTURE WILL PREVENT ANY CONVECTIVE ACTIVITY. THERE COULD BE A
LITTLE MORE IN THE WAY OF CIRRUS AS A WEAK DISTURBANCE ALOFT ROTATES
AROUND THE DEEP UPPER LOW EXPECTED OVER NEW ENGLAND...BUT IT WONT
SIGNIFICANTLY DENT THE AMOUNT OF SUNSHINE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE REGION WILL BE SANDWICHED BETWEEN TWO AREAS OF HIGH PRESSURE
EARLY IN THE WEEK...THE STRONGER OF THE TWO PASSING ACROSS THE
MID-ATLANTIC REGION AND THE OTHER OVER THE NORTHEAST GULF OF
MEXICO. DEEPENING MOISTURE WILL RESULT IN AT LEAST AN INCREASE IN
CLOUD COVER...BUT IT APPEARS THE RAIN-FREE CONDITIONS SHOULD
PERSIST THROUGH MEMORIAL DAY. ATLANTIC HIGH PRESSURE WILL THEN
BECOME ESTABLISHED THROUGH THE MIDDLE OF NEXT WEEK...SUPPORTING
MAINLY DIURNAL ISOLATED CONVECTION EACH AFTERNOON ALONG AND AHEAD
OF THE SEA BREEZE TUESDAY THROUGH THURSDAY. TEMPERATURES WILL
MODERATE TO NEAR NORMAL BY EARLY NEXT WEEK AND CONTINUE NEAR
SEASONAL NORMS THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
VFR THROUGH FRIDAY.
EXTENDED AVIATION...VFR CONDITIONS THROUGH THE WEEKEND.
&&
.MARINE...
WINDS WILL CONTINUE TO VEER TOWARD THE WEST AND WILL INCREASE IN
SPEED OVERNIGHT. WINDS AS HIGH AS 15-20 KT COULD DEVELOP ACROSS
WATERS BEYOND 20 NM LATE. SEAS WILL RANGE FROM 2-4FT WITHIN
NEARSHORE WATERS TO 3-5 FT BEYOND 20 NM. OFFSHORE WINDS WILL
CONTINUE FRIDAY...WITH WINDS VEERING TOWARD THE NORTHWEST
ESPECIALLY IN THE AFTERNOON.
THE MAIN PERIOD OF CONCERN WILL BE FRIDAY NIGHT BEHIND THE COLD
FRONT AS WINDS ACCELERATE FROM THE NORTH AND EVENTUALLY NORTH
NORTHEAST. WINDS AND SEAS WILL BE RIGHT AROUND SCA CRITERIA
OFFSHORE...BUT TOO MARGINAL TO ISSUE ANY HEADLINES AT THIS TIME.
WINDS AND SEAS WILL QUICKLY COME BACK DOWN SATURDAY AS THE
PRESSURE GRADIENT COLLAPSES WHILE HIGH PRESSURES SETTLES OVER THE
WATERS.
WINDS WILL BECOME DIURNALLY DRIVEN NEXT WEEK AS THE SURFACE
HIGH MOVES INTO THE ATLANTIC WITH A WEAK RIDGE STRETCHING WESTWARD
OVER THE CWA. SPEEDS SHOULD BE 15 KNOTS OR LESS THE FIRST HALF OF
NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENINGS. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE AS
ASTRONOMICAL FACTORS WILL CAUSE HIGHER THAN TYPICAL TIDES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...SPR
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...SPR
MARINE...FWA/SPR
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 240213
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1013 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
COLD FRONT IN THE UPSTATE AT 02Z WILL MOVE ACROSS THE REGION
OVERNIGHT. DRIER AIR ADVECTING INTO THE AREA...SHOWERS WILL REMAIN
NORTH OF THE REGION...SO REMOVED POPS FOR REST OF NIGHT WITH
CLEARING SKIES. TEMPERATURES FALLING INTO THE UPPER 50S TO LOWER
60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
DRYING BEHIND THE FRONT SHOULD DOMINATE FRIDAY THROUGH FRIDAY
NIGHT. MIXING ASSOCIATED WITH THE FRONT SUPPORTED THE WARMER
TEMPERATURE GUIDANCE TONIGHT. HIGH PRESSURE WILL BRING COOLER
DRIER CONDITIONS FRIDAY NIGHT AND SATURDAY. WILL GO WITH GFS MOS
GUIDANCE IN THE MID 40S FRIDAY NIGHT AND MODEL BLEND UPPER 70S
TO LOWER 80S SATURDAY. AIR MASS MODIFIES BY SATURDAY NIGHT WITH
LOWS IN THE LOWER 50S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH UPPER RIDGE WORKING
IN FROM THE WEST. BOTH MODELS SHOW A WEAK SURFACE FRONTAL BOUNDARY
WHICH REMAINS MAINLY TO THE NORTH BUT ECMWF SHOWS THE FRONT A
LITTLE BIT STRONGER THAN THE GFS. THE ECMWF ALSO KEEPS THE FRONT
A LITTLE FARTHER TO THE SOUTH. DRY TO START SUNDAY AND MONDAY BUT
BY THE END OF THE EXTENDED PERIOD...THE AIR MASS MOISTURE INCREASES
AND THE INSTABILITY INCREASES. EXPECT MORE DIURNAL SHOWERS AND
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY. HIGH TEMPERATURES
INCREASE FROM THE LOWER 80S SUNDAY TO THE MID 80S MONDAY AND
TUESDAY TO THE UPPER 80S BY WEDNESDAY. OVERNIGHT LOW TEMPERATURES
ARE EXPECTED TO BE IN THE UPPER 50S SUNDAY NIGHT BUT INCREASE TO
THE LOWER 60S FOR THE REST OF THE PERIOD.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
SURFACE AND/OR BOUNDARY LAYER WINDS ARE EXPECTED TO STAY UP SOME
TONIGHT...PLUS SOME DRIER AIR WILL FILTER IN BEHIND A WEAK SURFACE
TROUGH...THUS PRECLUDING ANY FOG/STRATUS THREAT. BREEZY CONDITIONS
EXPECTED FRIDAY...BEHIND A DRY COLD FRONT THAT WILL COME THROUGH IN
THE MORNING.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY FRIDAY AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WINDS APPEAR MARGINAL RED FLAG...EXPECT
SUSTAINED WINDS MAINLY BELOW 20 MPH. WIND GUSTS EXPECTED TO AROUND
25 MPH. FUEL MOISTURE IS HIGH REDUCING FIRE THREAT.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES FRIDAY NIGHT/SATURDAY MORNING WITH
LOWS IN THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 232352
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
752 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 800 PM...OVERALL COVERAGE OF SHOWERS AND THUNDERSTORMS HAS
DECREASED ACROSS THE UPSTATE AND THE NC PIEDMONT. SOME NEW SHOWER
ACTIVITY HAS TRIED TO GET GOING ACROSS THE HIGHER TERRAINS BUT LOOKS
TO BE STRUGGLING AS DAYTIME HEATING INDUCED INSTABILITY FALLS.
LATEST SURFACE OBSERVATIONS DO SHOW A FAIRLY EVIDENT WIND SHIFT TO
THE NNW ACROSS THE HIGHER TERRAINS AS THE BELOW MENTIONED FRONTAL
BOUNDARY MAKES ITS WAY INTO THE CWA. OTHERWISE...TOUCHED UP
TEMPERATURES AND MADE NO OTHER CHANGES TO THE FCST.
REMAINDER OF PREVIOUS DISCUSSION...
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AT KCLT...EXPECTING VFR CONDITIONS TO PREVAIL THROUGH THE ENTIRE TAF
PERIOD. LOOKS AS IF THERE MIGHT BE ENOUGH CONVECTIVE DEBRIS IN THE
REGION TO KEEP CIGS AT AROUND THE 12-15KFT LEVEL THROUGH MOST OF THE
EVENING BEFORE SCATTERING OUT BY DAYBREAK. WINDS WILL SHIFT TO A
MORE NNW COMPONENT AROUND THE 04Z TIMEFRAME AND SHOULD STAY AROUND
6-7KTS GENERALLY. OTHERWISE...WINDS WILL INCREASE AROUND 14Z FRIDAY
MORNING AS SFC PRESSURE GRADIENT TIGHTENS AND LOW LEVEL WINDS MIX
DOWN. THUS...WENT WITH PREVAILING 12KTS WITH 25KT GUSTS FOR THE
REMAINDER OF THE TAF PERIOD.
ELSEWHERE...VFR CONDITIONS CAN BE EXPECTED AT ALL TAF SITES THROUGH
THE PERIOD AND CIGS WILL IMPROVE THROUGHOUT THE EVENING. AS
WITH KCLT ABOVE...WINDS WILL BE THE GREATEST CONCERN ON FRIDAY AS
850MB FLOW ALOFT MIXES DOWN. THUS...ALL SITES HAVE GROUPS WITH
PREVAILING WINDS IN THE 10-12KT RANGE WITH GUST APPROACHING 25KTS.
KAVL LOOKS TO HAVE THE HIGHEST WIND POTENTIAL AS FLOW CHANNELS
THROUGH THE FRENCH BROAD VALLEY AND IS EXPECTED TO GUST NEAR 30KTS.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 98% MED 79% HIGH 91% HIGH 100%
KHKY HIGH 100% HIGH 94% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...CDG/PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...CDG
000
FXUS62 KCAE 232342
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
742 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SHOWERS AND THUNDERSTORMS MOVING INTO NORTHEAST SOUTH
CAROLINA...CLEARING ACROSS MIDLANDS. POPS DECREASING RAPIDLY
ACROSS THE REGION AS DRY AIR ADVECTS IN FROM THE UPSTATE AND NORTH
GEORGIA. LOWS UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
DRYING BEHIND THE FRONT SHOULD DOMINATE FRIDAY THROUGH FRIDAY
NIGHT. MIXING ASSOCIATED WITH THE FRONT SUPPORTED THE WARMER
TEMPERATURE GUIDANCE TONIGHT. HIGH PRESSURE WILL BRING COOLER
DRIER CONDITIONS FRIDAY NIGHT AND SATURDAY. WILL GO WITH GFS MOS
GUIDANCE IN THE MID 40S FRIDAY NIGHT AND MODEL BLEND UPPER 70S
TO LOWER 80S SATURDAY. AIR MASS MODIFIES BY SATURDAY NIGHT WITH
LOWS IN THE LOWER 50S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH UPPER RIDGE WORKING
IN FROM THE WEST. BOTH MODELS SHOW A WEAK SURFACE FRONTAL BOUNDARY
WHICH REMAINS MAINLY TO THE NORTH BUT ECMWF SHOWS THE FRONT A
LITTLE BIT STRONGER THAN THE GFS. THE ECMWF ALSO KEEPS THE FRONT
A LITTLE FARTHER TO THE SOUTH. DRY TO START SUNDAY AND MONDAY BUT
BY THE END OF THE EXTENDED PERIOD...THE AIR MASS MOISTURE INCREASES
AND THE INSTABILITY INCREASES. EXPECT MORE DIURNAL SHOWERS AND
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY. HIGH TEMPERATURES
INCREASE FROM THE LOWER 80S SUNDAY TO THE MID 80S MONDAY AND
TUESDAY TO THE UPPER 80S BY WEDNESDAY. OVERNIGHT LOW TEMPERATURES
ARE EXPECTED TO BE IN THE UPPER 50S SUNDAY NIGHT BUT INCREASE TO
THE LOWER 60S FOR THE REST OF THE PERIOD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
ONLY AN ISOLATED SHOWER OR THUNDERSTORM POSSIBLE THROUGH THIS
EVENING. CHANCES FAR TOO LOW TO INCLUDE MENTION IN THE TAFS. WINDS
ARE EXPECTED TO STAY UP SOME TONIGHT...PLUS SOME DRIER AIR WILL
FILTER IN BEHIND A WEAK SURFACE TROUGH...PRECLUDING ANY FOG/STRATUS
THREAT. BREEZY CONDITIONS EXPECTED FRIDAY...BEHIND A DRY COLD FRONT
THAT WILL COME THROUGH IN THE MORNING.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY FRIDAY AFTERNOON IS EXPECTED TO BE IN THE 20 TO
25 PERCENT RANGE. WINDS APPEAR MARGINAL RED FLAG...EXPECT
SUSTAINED WINDS MAINLY BELOW 20 MPH. WIND GUSTS EXPECTED TO AROUND
25 MPH. FUEL MOISTURE IS HIGH REDUCING FIRE THREAT.
&&
.CLIMATE...
MUCH BELOW NORMAL TEMPERATURES FRIDAY NIGHT/SATURDAY MORNING WITH
LOWS IN THE 40S.
COLUMBIA METRO AIRPORT RECORD LOW MAY 25TH...45 SET IN 1967
AUGUSTA BUSH FIELD RECORD LOW MAY 25TH.......43 SET IN 1951
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 232310
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
710 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION LATE TONIGHT...WITH DRY
HIGH PRESSURE BUILDING IN THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THIS EVENING...ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS...WITH
BEST COVERAGE ACROSS FAR NORTHERN COUNTIES...WILL CONTINUE TO FIRE
AND DISSIPATE ALONG AN INLAND DEWPOINT BOUNDARY AND THE SEA BREEZE
PINNED NEAR THE COAST. AFTER DARK...DIURNAL COOLING WILL TRANSLATE
TO DECREASING PRECIPITATION COVERAGE.
A COLD FRONT ACROSS THE OHIO/TENNESSEE VALLEY WILL MAKE STEADY
PROGRESS SOUTHEAST OVERNIGHT. ANY SHOWERS OR THUNDERSTORMS WILL
ACTUALLY HAVE DISSIPATED WELL BEFORE THE FRONT PUSHES INTO THE
REGION DURING THE PRE DAWN HOURS. HAVE THUS CAPPED RAIN CHANCES
BELOW 15 PERCENT BY MIDNIGHT. WINDS WILL STEADILY VEER FROM WEST
TO NORTHWEST BY DAYBREAK FRIDAY...WITH SKIES LIKELY MOSTLY CLEAR
BY SUNRISE.
LOW TEMPERATURES WILL RANGE FROM THE LOW TO MID 60S AWAY FROM THE
IMMEDIATE COASTLINE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
THE WEATHER WILL BE RELATIVELY QUIET DURING THIS PERIOD AS HIGH
PRESSURE BUILDS IN FROM THE NORTH ON FRIDAY...SETTLING OVER THE AREA
FOR THE WEEKEND. FRIDAY WILL BE THE WARMEST OF THE THREE DAYS AS
NORTHWESTERLY DOWNSLOPE FLOW WILL ALLOW FOR A LITTLE COMPRESSIONAL
HEATING AT LOW LEVELS. AFTERNOON MAX TEMPS WILL MANAGE TO GET TO
NEAR NORMAL UNDER MOSTLY SUNNY SKIES. THE WINDS MAY GET A BIT BREEZY
DURING THE LATE MORNING AND EARLY AFTERNOON HOURS WITH GOOD MIXING
IN THE BOUNDARY LAYER ALLOWING SOMEWHAT STRONGER WINDS TO MIX TO THE
SURFACE.
FRIDAY NIGHT...STRONG COOL ADVECTION SETTLES IN...WITH TEMPERATURES
DROPPING ALL NIGHT. RISING HEIGHTS ALOFT WILL HELP PROMOTE LOW LEVEL
SUBSIDENCE...KEEPING SKIES CLEAR. TEMPS WILL DROP INTO THE UPPER 40S
TO NEAR 50 WEST OF INTERSTATE 95...WITH LOWER 50S ELSEWHERE. A
PERSISTENT 5 TO 10 KNOT WIND WILL KEEP TEMPS FROM DROPPING EVEN
LOWER.
SATURDAY WILL BE COOL AND SUNNY AS A BUBBLE AREA OF HIGH PRESSURE
SETS UP IN THE NEIGHBORHOOD. DEW POINTS WILL DROP INTO THE 30S BY
AFTERNOON AWAY FROM THE COAST...WHICH IS VERY LOW FOR MEMORIAL DAY
WEEKEND. RELATIVE HUMIDITY VALUES BY THEMSELVES WOULD BE LOW
ENOUGH FOR FIRE WEATHER CONCERNS...BUT THE WINDS WILL BE GENERALLY
LESS THAN 10 KNOTS.
NOT MUCH CHANGE EXPECTED ON SUNDAY WITH THE HIGH REMAINING CLOSE BY.
A WEAK LEE TROF MAY DEVELOP BY AFTERNOON IN THE MIDLANDS...ALLOWING
FOR A BIT MORE ROBUST SEA BREEZE TO FORM...BUT THE LACK OF LOW LEVEL
MOISTURE WILL PREVENT ANY CONVECTIVE ACTIVITY. THERE COULD BE A
LITTLE MORE IN THE WAY OF CIRRUS AS A WEAK DISTURBANCE ALOFT ROTATES
AROUND THE DEEP UPPER LOW EXPECTED OVER NEW ENGLAND...BUT IT WONT
SIGNIFICANTLY DENT THE AMOUNT OF SUNSHINE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE REGION WILL BE SANDWICHED BETWEEN TWO AREAS OF HIGH PRESSURE
EARLY IN THE WEEK...THE STRONGER OF THE TWO PASSING ACROSS THE
MID-ATLANTIC REGION AND THE OTHER OVER THE NORTHEAST GULF OF
MEXICO. DEEPENING MOISTURE WILL RESULT IN AT LEAST AN INCREASE IN
CLOUD COVER...BUT IT APPEARS THE RAIN-FREE CONDITIONS SHOULD
PERSIST THROUGH MEMORIAL DAY. ATLANTIC HIGH PRESSURE WILL THEN
BECOME ESTABLISHED THROUGH THE MIDDLE OF NEXT WEEK...SUPPORTING
MAINLY DIURNAL ISOLATED CONVECTION EACH AFTERNOON ALONG AND AHEAD
OF THE SEA BREEZE TUESDAY THROUGH THURSDAY. TEMPERATURES WILL
MODERATE TO NEAR NORMAL BY EARLY NEXT WEEK AND CONTINUE NEAR
SEASONAL NORMS THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR THROUGH FRIDAY.
EXTENDED AVIATION...VFR CONDITIONS THROUGH THE WEEKEND.
&&
.MARINE...
SOUTHERLY WINDS THIS AFTERNOON WILL VEER OFFSHORE OVERNIGHT...AS A
COLD FRONT SHIFTS THROUGH THE AREA BY DAYBREAK FRIDAY. WIND SPEEDS
WILL PEAK AROUND 15 KT...YET THE OFFSHORE FETCH WILL LIMIT THE
SEAS TO NO HIGHER THAN 4 FT.
THE MAIN PERIOD OF CONCERN WILL BE FRIDAY NIGHT BEHIND THE COLD
FRONT AS WINDS ACCELERATE FROM THE NORTH AND EVENTUALLY NORTH
NORTHEAST. WINDS AND SEAS WILL BE RIGHT AROUND SCA CRITERIA
OFFSHORE...BUT TOO MARGINAL TO ISSUE ANY HEADLINES AT THIS TIME.
WINDS AND SEAS WILL QUICKLY COME BACK DOWN SATURDAY AS THE
PRESSURE GRADIENT COLLAPSES WHILE HIGH PRESSURES SETTLES OVER THE
WATERS.
WINDS WILL BECOME DIURNALLY DRIVEN NEXT WEEK AS THE SURFACE
HIGH MOVES INTO THE ATLANTIC WITH A WEAK RIDGE STRETCHING WESTWARD
OVER THE CWA. SPEEDS SHOULD BE 15 KNOTS OR LESS THE FIRST HALF OF
NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENINGS. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE AS
ASTRONOMICAL FACTORS WILL CAUSE HIGHER THAN TYPICAL TIDES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...SPR/WMS
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...SPR
MARINE...FWA/JAQ/SPR
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 232103
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
503 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
INSTABILITY ACROSS THE MIDLANDS WEAK TO MODERATE HOWEVER DRIER AIR
ADVECTING EAST FROM GEORGIA. RADAR SHOWING A FEW SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS EASTERN/NORTH MIDLANDS THIS AFTERNOON.
CLUSTER OF STRONGER THUNDERSTORMS IN THE UPSTATE MOVING SOUTHEAST.
ALTHOUGH DRIER AIR WILL LIMIT CONVECTIVE COVERAGE...LATEST HIGH
RESOLUTION MODELS SUPPORT SCATTERED CONVECTION MAINLY NORTH AND
EAST OF COLUMBIA EARLY THIS EVENING. DRY MID LEVEL AIR SUPPORTS A
HAIL THREAT...BUT OVERALL SEVERE THREAT APPEARS LOW.
TONIGHT...A 20 PERCENT CHANCE EARLY. PLAN ON NO POPS IN THE WEST
AS DRIER AIR MOVES IN FROM THE WEST WITH THE COLD FRONT. LOWS
UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
DRYING BEHIND THE FRONT SHOULD DOMINATE FRIDAY THROUGH FRIDAY
NIGHT. MIXING ASSOCIATED WITH THE FRONT SUPPORTED THE WARMER
TEMPERATURE GUIDANCE TONIGHT. HIGH PRESSURE WILL BRING COOLER
DRIER CONDITIONS FRIDAY NIGHT AND SATURDAY. WILL GO WITH GFS MOS
GUIDANCE IN THE MID 40S FRIDAY NIGHT AND MODEL BLEND UPPER 70S
TO LOWER 80S SATURDAY. AIR MASS MODIFIES BY SATURDAY NIGHT WITH
LOWS IN THE LOWER 50S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH UPPER RIDGE WORKING
IN FROM THE WEST. BOTH MODELS SHOW A WEAK SURFACE FRONTAL BOUNDARY
WHICH REMAINS MAINLY TO THE NORTH BUT ECMWF SHOWS THE FRONT A
LITTLE BIT STRONGER THAN THE GFS. THE ECMWF ALSO KEEPS THE FRONT
A LITTLE FARTHER TO THE SOUTH. DRY TO START SUNDAY AND MONDAY BUT
BY THE END OF THE EXTENDED PERIOD...THE AIR MASS MOISTURE INCREASES
AND THE INSTABILITY INCREASES. EXPECT MORE DIURNAL SHOWERS AND
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY. HIGH TEMPERATURES
INCREASE FROM THE LOWER 80S SUNDAY TO THE MID 80S MONDAY AND
TUESDAY TO THE UPPER 80S BY WEDNESDAY. OVERNIGHT LOW TEMPERATURES
ARE EXPECTED TO BE IN THE UPPER 50S SUNDAY NIGHT BUT INCREASE TO
THE LOWER 60S FOR THE REST OF THE PERIOD.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS ARE EXPECTED THROUGH THE 24 HOUR TAF PERIOD.
A SERIES OF WEAK UPPER IMPULSES WILL COME THROUGH LATER TODAY
THROUGH EARLY TONIGHT. WEAK SURFACE TROUGH WILL MOVE THROUGH.
SATELLITE WATER VAPOR IMAGERY INDICATING DRY AIR ALOFT. MESOANALYSIS
INDICATES MODERATE INSTABILITIES. HIGH RES MODELS GENERALLY
PROJECTING LIMITED AREAL COVERAGE OF CONVECTION THROUGH THIS
EVENING...AND MAINLY FAVORING THE NORTH AND EAST FA. LATEST RADAR
INDICATES A FEW SHOWERS DEVELOPING OVER THE CENTRAL MIDLANDS. WILL
HANDLE WITH VCSH AT CAE/CUB/OGB IN THE NEAR TERM...WITH POSSIBILITY
OF HAVING TO AMEND OGB TO INCLUDE A TEMPO OR PREDOMINATE MENTION IN
THE NEAR TERM. WINDS STAYING UP TONIGHT...ALONG WITH SOME DRIER AIR
FILTERING IN...TO PRECLUDE FOG/STRATUS THREAT. BREEZY CONDITIONS
EXPECTED FRIDAY.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 232100
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
500 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 445 PM...SCATTERED CONVECTIVE ACTIVITY CONTINUES ACROSS
NORTHERN MOST PORTIONS OF THE UPSTATE...AND INTO THE THE NC
PIEDMONT. VISIBLE SATELLITE TRENDS ARE ACTUALLY SHOWING A DECREASE
IN THE CU FIELD ACROSS THE UPSTATE....THEREFORE ADJUSTED TEMPERATURE
TRENDS TO ACCOUNT FOR THIS AND ANY OUTFLOW COOLING FROM ADJACENT
CONVECTION. EXTENDED ZONE OF LIKELY POPS IN THE NEAR TERM FURTHER
WEST ACROSS THE PIEDMONT AS NEAR TERM GUIDANCE KEEPS CURRENT
ACTIVITY GOING IN THIS REGION FOR THE NEXT 3-4 HOURS. OTHERWISE...NO
OTHER CHANGES WERE MADE.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF MID AFTERNOON...CANNOT RULE OUT ONE OR TWO SEVERE CELLS GIVEN
SUFFICIENT CAPE ON THE LATEST LAPS ANALYSIS AND SOME DCAPE AS
WELL...BUT NEITHER IS AS GOOD AS YESTERDAY. NE GEORGIA AND THE
UPSTATE WILL HAVE THE LEAST CHANCE OF PRECIP BECAUSE OF A LACK OF
TRIGGER.
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
AT KCLT FOR 21Z UPDATE...HAVE HELD ONTO A TWO HOUR WINDOW OF
THUNDERSTORMS FROM EARLIER TAF ISSUANCE IN THE 21Z TO 23Z TIME RANGE
PER THE 4KM WRF MODEL AND RECENT RADAR TRENDS. THUS...KEPT PREVIOUS
TEMPO GROUP AS IS WITH THE ONLY CHANGE BEING TO WINDS WITH MENTION
OF VRB10 GUSTING TO 20KTS ADJACENT TO ANY THUNDERSTORMS. THE FRONT
SHOULD FINALLY CROSS THE REGION DURING THE MIDDLE PART OF THE
EVENING WHICH WILL CLEAR OUT THE LOW CLOUDS AND SHIFT THE WIND FROM
SW TO NW...BY 04Z AT THE LATEST. CONDITIONS SHOULD BE VFR FROM THAT
POINT ONWARD. ON FRIDAY...ONCE THE WINDS COME UP DURING MID
MORNING...EXPECT FREQUENT GUSTS FROM THE NW.
ELSEWHERE...SIMILAR CHANCES FOR MVFR CEILING UNTIL 20Z OR SO WHEN
THE BOUNDARY LAYER LIFTS THE CLOUD BASES ABOVE 030. OTHERWISE...
LESS OF A CHANCE FOR CONVECTIVE ACTIVITY. ONLY KHKY WARRANTS A
VICINITY THUNDERSTORM FOR THE TIME BEING. EXPECT VFR CONDITIONS
AFTER FRONTAL PASSAGE...WHICH SHOULD BE LATE AFTERNOON TO EARLY
EVENING. SOME UPSLOPE SHOWERS COULD OCCUR ALONG THE TN BORDER...BUT
THIS IS NOT EXPECTED TO AFFECT KAVL. WINDS SHOULD BE STRONG AND
GUSTY FROM THE NW ON FRIDAY.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 92% MED 76% HIGH 85% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 93% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...CDG/PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...CDG/PM
000
FXUS62 KCHS 231947
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
347 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION LATE TONIGHT...WITH DRY
HIGH PRESSURE BUILDING IN THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
DESPITE AN UPPER SHORTWAVE MOVING OVER THE AREA AND A PRE-FRONTAL
SURFACE TROUGH DIRECTLY ACROSS THE MID ATLANTIC AND SOUTHEAST
STATES...CONVECTION HAS STRUGGLED TO DEVELOP BY LATE AFTERNOON.
INSTABILITY PARAMETERS ARE RELATIVELY WEAK FOR LATE SPRING...AND
WITH DEEP MOISTURE STEADILY DIMINISHING FROM WEST TO
EAST...ISOLATED CONVECTION HAS MAINLY BEEN IN THE FORM OF SHOWERS
AND WEAK BRIEF THUNDERSTORMS. HAVE DECREASED RAIN POTENTIAL FOR
THE REMAINDER OF THE DAYTIME HOURS...INDICATING JUST SLIGHT
CHANCES MAINLY ACROSS THE CHARLESTON TRI COUNTY REGION AND ALONG
THE SEABREEZE FROM COASTAL SOUTH CAROLINA THROUGH COASTAL GEORGIA.
DEPENDING UPON RADAR TRENDS DURING THE NEXT HOUR OR TWO...THESE
RAIN CHANCES COULD EVEN BE OVERDONE THROUGH THE EVENING.
A COLD FRONT ACROSS THE OHIO/TENNESSEE VALLEY WILL MAKE STEADY
PROGRESS SOUTHEAST OVERNIGHT. ANY SHOWERS OR THUNDERSTORMS WILL
ACTUALLY HAVE DISSIPATED WELL BEFORE THE FRONT PUSHES INTO THE
REGION DURING THE PRE DAWN HOURS. HAVE THUS CAPPED RAIN CHANCES
BELOW 15 PERCENT BY MIDNIGHT. WINDS WILL STEADILY VEER FROM WEST
TO NORTHWEST BY DAYBREAK FRIDAY...WITH SKIES LIKELY MOSTLY CLEAR
BY SUNRISE.
LOW TEMPERATURES WILL RANGE FROM THE LOW TO MID 60S AWAY FROM THE
IMMEDIATE COASTLINE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
THE WEATHER WILL BE RELATIVELY QUIET DURING THIS PERIOD AS HIGH
PRESSURE BUILDS IN FROM THE NORTH ON FRIDAY...SETTLING OVER THE AREA
FOR THE WEEKEND. FRIDAY WILL BE THE WARMEST OF THE THREE DAYS AS
NORTHWESTERLY DOWNSLOPE FLOW WILL ALLOW FOR A LITTLE COMPRESSIONAL
HEATING AT LOW LEVELS. AFTERNOON MAX TEMPS WILL MANAGE TO GET TO
NEAR NORMAL UNDER MOSTLY SUNNY SKIES. THE WINDS MAY GET A BIT BREEZY
DURING THE LATE MORNING AND EARLY AFTERNOON HOURS WITH GOOD MIXING
IN THE BOUNDARY LAYER ALLOWING SOMEWHAT STRONGER WINDS TO MIX TO THE
SURFACE.
FRIDAY NIGHT...STRONG COOL ADVECTION SETTLES IN...WITH TEMPERATURES
DROPPING ALL NIGHT. RISING HEIGHTS ALOFT WILL HELP PROMOTE LOW LEVEL
SUBSIDENCE...KEEPING SKIES CLEAR. TEMPS WILL DROP INTO THE UPPER 40S
TO NEAR 50 WEST OF INTERSTATE 95...WITH LOWER 50S ELSEWHERE. A
PERSISTENT 5 TO 10 KNOT WIND WILL KEEP TEMPS FROM DROPPING EVEN
LOWER.
SATURDAY WILL BE COOL AND SUNNY AS A BUBBLE AREA OF HIGH PRESSURE
SETS UP IN THE NEIGHBORHOOD. DEW POINTS WILL DROP INTO THE 30S BY
AFTERNOON AWAY FROM THE COAST...WHICH IS VERY LOW FOR MEMORIAL DAY
WEEKEND. RELATIVE HUMIDITY VALUES BY THEMSELVES WOULD BE LOW
ENOUGH FOR FIRE WEATHER CONCERNS...BUT THE WINDS WILL BE GENERALLY
LESS THAN 10 KNOTS.
NOT MUCH CHANGE EXPECTED ON SUNDAY WITH THE HIGH REMAINING CLOSE BY.
A WEAK LEE TROF MAY DEVELOP BY AFTERNOON IN THE MIDLANDS...ALLOWING
FOR A BIT MORE ROBUST SEA BREEZE TO FORM...BUT THE LACK OF LOW LEVEL
MOISTURE WILL PREVENT ANY CONVECTIVE ACTIVITY. THERE COULD BE A
LITTLE MORE IN THE WAY OF CIRRUS AS A WEAK DISTURBANCE ALOFT ROTATES
AROUND THE DEEP UPPER LOW EXPECTED OVER NEW ENGLAND...BUT IT WONT
SIGNIFICANTLY DENT THE AMOUNT OF SUNSHINE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE REGION WILL BE SANDWICHED BETWEEN TWO AREAS OF HIGH PRESSURE
EARLY IN THE WEEK...THE STRONGER OF THE TWO PASSING ACROSS THE
MID-ATLANTIC REGION AND THE OTHER OVER THE NORTHEAST GULF OF
MEXICO. DEEPENING MOISTURE WILL RESULT IN AT LEAST AN INCREASE IN
CLOUD COVER...BUT IT APPEARS THE RAIN-FREE CONDITIONS SHOULD
PERSIST THROUGH MEMORIAL DAY. ATLANTIC HIGH PRESSURE WILL THEN
BECOME ESTABLISHED THROUGH THE MIDDLE OF NEXT WEEK...SUPPORTING
MAINLY DIURNAL ISOLATED CONVECTION EACH AFTERNOON ALONG AND AHEAD
OF THE SEA BREEZE TUESDAY THROUGH THURSDAY. TEMPERATURES WILL
MODERATE TO NEAR NORMAL BY EARLY NEXT WEEK AND CONTINUE NEAR
SEASONAL NORMS THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT BOTH KCHS AND KSAV THROUGH 18Z
FRIDAY. ISOLATED SHOWER ACTIVITY WILL CONTINUE FOR THE REMAINDER
OF THE AFTERNOON HOURS...HOWEVER DO NOT EXPECT ANY SIGNIFICANT
IMPACTS AT EITHER TERMINAL. ANY SHOWERS/THUNDERSTORMS WILL
STEADILY DIMINISH IN COVERAGE...WHILE SKIES BEGIN CLEARING THIS
EVENING. A COLD FRONT PROGRESSING THROUGH THE REGION OVERNIGHT
WILL SUPPORT STEADILY VEERING WINDS...WITH NORTHWEST FLOW EXPECTED
BY DAYBREAK FRIDAY.
EXTENDED AVIATION...VFR CONDITIONS THROUGH THE WEEKEND.
&&
.MARINE...
SOUTHERLY WINDS THIS AFTERNOON WILL VEER OFFSHORE OVERNIGHT...AS A
COLD FRONT SHIFTS THROUGH THE AREA BY DAYBREAK FRIDAY. WIND SPEEDS
WILL PEAK AROUND 15 KT...YET THE OFFSHORE FETCH WILL LIMIT THE
SEAS TO NO HIGHER THAN 4 FT.
THE MAIN PERIOD OF CONCERN WILL BE FRIDAY NIGHT BEHIND THE COLD
FRONT AS WINDS ACCELERATE FROM THE NORTH AND EVENTUALLY NORTH
NORTHEAST. WINDS AND SEAS WILL BE RIGHT AROUND SCA CRITERIA
OFFSHORE...BUT TOO MARGINAL TO ISSUE ANY HEADLINES AT THIS TIME.
WINDS AND SEAS WILL QUICKLY COME BACK DOWN SATURDAY AS THE
PRESSURE GRADIENT COLLAPSES WHILE HIGH PRESSURES SETTLES OVER THE
WATERS.
WINDS WILL BECOME DIURNALLY DRIVEN NEXT WEEK AS THE SURFACE
HIGH MOVES INTO THE ATLANTIC WITH A WEAK RIDGE STRETCHING WESTWARD
OVER THE CWA. SPEEDS SHOULD BE 15 KNOTS OR LESS THE FIRST HALF OF
NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENINGS. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE AS
ASTRONOMICAL FACTORS WILL CAUSE HIGHER THAN TYPICAL TIDES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...WMS
MARINE...FWA/JAQ
TIDES/COASTAL FLOODING...FWA
000
FXUS62 KCAE 231936
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
336 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THIS AFTERNOON...MODEL FORECAST SOUNDINGS SHOW A CONDITIONALLY
UNSTABLE AIRMASS WITH A WEAK MID LEVEL CAP. MODELS GIVE AFTERNOON
CAPES 1000-2000 J/KG...LIS -5/-6 AND TOTALS AROUND 45. PW VALUES
INITIALLY AROUND 1.4 INCHES BUT DRIER AIR WORKS IN FROM WEST TO
LOWER PW TO 1.20 INCHES. KIS LESS THAN 30 AS MOISTURE IS MAINLY
BELOW 10 KFT. HOWEVER...AFTERNOON HEATING MAY LIFT MOISTURE ENOUGH
FOR A FEW THUNDERSTORMS MAINLY IN THE EAST PART. SPC HAS AREA IN
GENERAL THUNDERSTORMS OUTLOOK BUT IF HIGH ELEVATED CORES DEVELOP
THE POTENTIAL EXISTS FOR PERHAPS ISOLATED STRONG TO SEVERE STORMS
BUT AGAIN MAINLY IN THE EAST. HAVE MAINLY 20-30 PERCENT CHANCE BUT
IN FAR EAST AND NORTHEAST WILL KEEP 40-60 PERCENT CHANCE. HIGH
TEMPERATURES IN THE MID TO UPPER 80S.
TONIGHT...A 20 PERCENT CHANCE IN THE EAST DURING THE EVENING.
PLAN ON NO POPS IN THE WEST AS DRIER AIR MOVES IN FROM THE WEST
WITH THE COLD FRONT. LOWS UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
DRYING BEHIND THE FRONT SHOULD DOMINATE FRIDAY THROUGH FRIDAY
NIGHT. MIXING ASSOCIATED WITH THE FRONT SUPPORTED THE WARMER
TEMPERATURE GUIDANCE TONIGHT. HIGH PRESSURE WILL BRING COOLER
DRIER CONDITIONS FRIDAY NIGHT AND SATURDAY. WILL GO WITH GFS MOS
GUIDANCE IN THE MID 40S FRIDAY NIGHT AND MODEL BLEND UPPER 70S
TO LOWER 80S SATURDAY. AIRMASS MODIFIES BY SATURDAY NIGHT WITH
LOWS IN THE LOWER 50S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH UPPER RIDGE WORKING
IN FROM THE WEST. BOTH MODELS SHOW A WEAK SURFACE FRONTAL BOUNDARY
WHICH REMAINS MAINLY TO THE NORTH BUT ECMWF SHOWS THE FRONT A
LITTLE BIT STRONGER THAN THE GFS. THE ECMWF ALSO KEEPS THE FRONT
A LITTLE FARTHER TO THE SOUTH. DRY TO START SUNDAY AND MONDAY BUT
BY THE END OF THE EXTENDED PERIOD...THE AIRMASS MOISTURE INCREASES
AND THE INSTABILITY INCREASES. EXPECT MORE DIURNAL SHOWERS AND
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY. HIGH TEMPERATURES
INCREASE FROM THE LOWER 80S SUNDAY TO THE MID 80S MONDAY AND
TUESDAY TO THE UPPER 80S BY WEDNESDAY. OVERNIGHT LOW TEMPERATURES
ARE EXPECTED TO BE IN THE UPPER 50S SUNDAY NIGHT BUT INCREASE TO
THE LOWER 60S FOR THE REST OF THE PERIOD.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS ARE EXPECTED THROUGH THE 24 HOUR TAF PERIOD.
A SERIES OF WEAK UPPER IMPULSES WILL COME THROUGH LATER TODAY
THROUGH EARLY TONIGHT. WEAK SURFACE TROUGH WILL MOVE THROUGH.
SATELLITE WATER VAPOR IMAGERY INDICATING DRY AIR ALOFT. MESOANALYSIS
INDICATES MODERATE INSTABILITIES. HIGH RES MODELS GENERALLY
PROJECTING LIMITED AREAL COVERAGE OF CONVECTION THROUGH THIS
EVENING...AND MAINLY FAVORING THE NORTH AND EAST FA. LATEST RADAR
INDICATES A FEW SHOWERS DEVELOPING OVER THE CENTRAL MIDLANDS. WILL
HANDLE WITH VCSH AT CAE/CUB/OGB IN THE NEAR TERM...WITH POSSIBILITY
OF HAVING TO AMEND OGB TO INCLUDE A TEMPO OR PREDOMINATE MENTION IN
THE NEAR TERM. WINDS STAYING UP TONIGHT...ALONG WITH SOME DRIER AIR
FILTERING IN...TO PRECLUDE FOG/STRATUS THREAT. BREEZY CONDITIONS
EXPECTED FRIDAY.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCAE 231843
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
243 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THIS AFTERNOON...MODEL FORECAST SOUNDINGS SHOW A CONDITIONALLY
UNSTABLE AIRMASS WITH A WEAK MID LEVEL CAP. MODELS GIVE AFTERNOON
CAPES 1000-2000 J/KG...LIS -5/-6 AND TOTALS AROUND 45. PW VALUES
INITIALLY AROUND 1.4 INCHES BUT DRIER AIR WORKS IN FROM WEST TO
LOWER PW TO 1.20 INCHES. KIS LESS THAN 30 AS MOISTURE IS MAINLY
BELOW 10 KFT. HOWEVER...AFTERNOON HEATING MAY LIFT MOISTURE ENOUGH
FOR A FEW THUNDERSTORMS MAINLY IN THE EAST PART. SPC HAS AREA IN
GENERAL THUNDERSTORMS OUTLOOK BUT IF HIGH ELEVATED CORES DEVELOP
THE POTENTIAL EXISTS FOR PERHAPS ISOLATED STRONG TO SEVERE STORMS
BUT AGAIN MAINLY IN THE EAST. HAVE MAINLY 20-30 PERCENT CHANCE BUT
IN FAR EAST AND NORTHEAST WILL KEEP 40-60 PERCENT CHANCE. HIGH
TEMPERATURES IN THE MID TO UPPER 80S.
TONIGHT...A 20 PERCENT CHANCE IN THE EAST DURING THE EVENING.
PLAN ON NO POPS IN THE WEST AS DRIER AIR MOVES IN FROM THE WEST
WITH THE COLD FRONT. LOWS UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
DRYING BEHIND THE FRONT SHOULD DOMINATE FRIDAY THROUGH FRIDAY
NIGHT. MIXING ASSOCIATED WITH THE FRONT SUPPORTED THE WARMER
TEMPERATURE GUIDANCE TONIGHT. HIGH PRESSURE WILL BRING COOLER
DRIER CONDITIONS FRIDAY NIGHT AND SATURDAY. WILL GO WITH GFS MOS
GUIDANCE IN THE MID 40S FRIDAY NIGHT AND MODEL BLEND UPPER 70S
TO LOWER 80S SATURDAY. AIRMASS MODIFIES BY SATURDAY NIGHT WITH
LOWS IN THE LOWER 50S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH UPPER RIDGE WORKING
IN FROM THE WEST. BOTH MODELS SHOW A WEAK SURFACE FRONTAL BOUNDARY
WHICH REMAINS MAINLY TO THE NORTH BUT ECMWF SHOWS THE FRONT A
LITTLE BIT STRONGER THAN THE GFS. THE ECMWF ALSO KEEPS THE FRONT
A LITTLE FARTHER TO THE SOUTH. DRY TO START SUNDAY AND MONDAY BUT
BY THE END OF THE EXTENDED PERIOD...THE AIRMASS MOISTURE INCREASES
AND THE INSTABILITY INCREASES. EXPECT MORE DIURNAL SHOWERS AND
THUNDERSTORMS TUESDAY THROUGH WEDNESDAY. HIGH TEMPERATURES
INCREASE FROM THE LOWER 80S SUNDAY TO THE MID 80S MONDAY AND
TUESDAY TO THE UPPER 80S BY WEDNESDAY. OVERNIGHT LOW TEMPERATURES
ARE EXPECTED TO BE IN THE UPPER 50S SUNDAY NIGHT BUT INCREASE TO
THE LOWER 60S FOR THE REST OF THE PERIOD.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
SATELLITE SHOWS PLENTY OF SC/CU AROUND THIS EARLY AFTERNOON. MOST
TAF SITES HAVE RETURNED TO VFR CONDITIONS...EXCEPT BOTH AGS/DNL
REPORTING MVFR CONDITIONS. EXPECT WITH ADDITIONAL DAYTIME HEATING
THAT CLOUD BASIS WILL RISE BETWEEN 19Z TO 20Z AND VFR CONDITIONS
WILL RETURN. AT THIS TIME...CONVECTION APPEARS TO BE MAINLY
CONCENTRATED ACROSS THE NORTHERN MIDLANDS/PEE DEE AND ALONG THE
COAST. THIS IS IN GOOD AGREEMENT WITH LOCAL/SPC WRF MODEL RUNS. WILL
CONTINUE WITH VFR CONDITIONS THROUGH THE PERIOD. WITH PASSAGE OF
COLD FRONT LATE THIS EVENING/OVERNIGHT...MODELS INDICATE A 30 KT LOW
LEVEL JET. THIS WILL KEEP WINDS UP SLIGHTLY OVERNIGHT BEFORE
BECOMING MORE BREEZE ON FRIDAY. ON FRIDAY...WINDS WILL BE FROM THE
NORTHWEST BEHIND THE FRONT AND BREEZY WITH WINDS AVERAGE 10 TO 15
KTS WITH GUSTS UP TO 25 KTS AT TIMES.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 231837
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
237 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF MID AFTERNOON...A FEW SHOWERS HAVE POPPED UP QUICKLY NEAR THE
BLUE RIDGE. THESE SHOULD BE DRIVEN EASTWARD OVER THE FOOTHILLS AND
WESTERN PIEDMONT THROUGH LATE AFTERNOON. SATELLITE IMAGERY SHOWS
SOME ENHANCED CU OVER THE RIDGETOPS...SO ADDITIONAL DEVELOPMENT IS
POSSIBLE. THE CURRENT POP FCST...WITH THE HIGHEST VALUES E OF
I-77... STILL LOOKS OKAY. CANNOT RULE OUT ONE OR TWO SEVERE CELLS
GIVEN SUFFICIENT CAPE ON THE LATEST LAPS ANALYSIS AND SOME DCAPE AS
WELL...BUT NEITHER IS AS GOOD AS YESTERDAY. NE GEORGIA AND THE
UPSTATE WILL HAVE THE LEAST CHANCE OF PRECIP BECAUSE OF A LACK OF
TRIGGER.
THE CONVECTION WILL BE SHUNTED EAST BY THE VEERING FLOW AHEAD OF THE
MAIN COLD FRONT...WHICH IS EXPECTED TO CROSS THE FCST AREA THIS
EVENING AS A SHORT WAVE ROUNDS THE BOTTOM OF THE UPPER TROF AND
SWINGS IT EASTWARD...CARRYING MOST OF THE CLOUDS AND SHOWERS WITH
IT. EXPECT SOME LINGERING SHOWER CHANCE ON THE TN BORDER THROUGH
FRIDAY MORNING WITH MOISTURE BEING FORCED UPWARD BY THE INCREASING
NW FLOW.
ON FRIDAY...IT LOOKS LIKE A BREEZY DAY WITH A DECENT PRESSURE
GRADIENT AS HIGH PRESSURE BUILDS IN FROM THE NW. AN EVEN MORE
DYNAMIC SHORT WAVE WILL ROUND THE BASE OF THE TROF AND CARRY THE
TROF AXIS FARTHER EAST DURING THE DAY...BUT THIS WAVE HAS NO
MOISTURE TO WORK WITH THIS FAR SOUTH. MIXING WILL BE RELATIVELY
SHALLOW BECAUSE OF A STRONG INVERSION...WHICH WILL PREVENT THE
TAPPING OF THE MUCH STRONGER WINDS AROUND 850 MB. THUS WE SHOULD
AVOID ANY WIND ADVISORY ISSUES. HIGH TEMPS WILL BE A FEW CATEGORIES
COOLER THAN TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM THURSDAY...A STRONG UPPER LOW WILL MOVE UP THE EAST
COAST FRIDAY NIGHT AS AN UPPER RIDGE BUILDS OVER THE CENTRAL PART OF
THE COUNTRY. THIS WILL ALLOW A COOL NW FLOW TO CONTINUE ACROSS THE
SOUTHERN APPALACHIANS THROUGH THE WEEKEND. AT THE SURFACE...A RIDGE
OF HIGH PRESSURE WITH CANADIAN ORIGIN IS FORECAST TO EXTEND FROM THE
GREAT LAKES SOUTHWARD TO FLORIDA FRIDAY NIGHT. THE HIGH WILL CONTROL
THE WEATHER THROUGH SATURDAY PRODUCING GENERALLY CLEAR AND
SEASONALLY COOL WEATHER. IN FACT...SOME SHELTERED MOUNTAIN VALLEYS
COULD SEE SOME SOME SCATTERED FROST FRI NIGHT PARTICULARLY IN THE
LITTLE TN VALLEY.
ON SUNDAY...AN UPPER IMPULSE IN THE NW FLOW ALOFT WILL CROSS THE
AREA ALONG WITH A WEAK BACKDOOR SURFACE FRONT. LOW LEVEL MOISTURE
WILL BE LACKING...BUT MODEL TIME HEIGHTS SHOW MID AND UPPER LEVEL
MOISTURE INCREASING WHICH MEANS AN INCREASE IN CLOUD COVER FOR SAT
NIGHT INTO SUNDAY. MODEL QPF RESPONSE IS QUITE MINIMAL ON SUNDAY AND
ANYTHING THAT DOES FALL WOULD PROBABLY BE JUST A FEW SPRINKLES OVER
THE MOUNTAINS.
USED A MODEL BLEND FOR TEMPS WHICH ADVERTISES WELL BELOW AVERAGE
TEMPERATURES FOR THE ENTIRE WEEKEND. MIN TEMPS FRI NIGHT WILL FALL
INTO THE UPPER 30S OVER MANY MOUNTAIN LOCATIONS WITH 40S COMMON
ELSEWHERE. MAX TEMPS WILL BE IN THE 70S...EXCEPT MID 60S TO AROUND
70 MOUNTAIN VALLEYS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM THURSDAY...THE 06Z/12Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
HOLDS STATIONARY OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK
IMPULSES TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A
RATHER UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS
THE RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUNS.
WPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR GSP OFFICIAL/GFS/ECM WHICH WOULD
PUT A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK. IF THE GFS SOLUTION VERIFIES...MAX
TEMPS WOULD BE ABOUT A CATEGORY HIGHER EACH DAY.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...MVFR CIG RESTRICTION SHOULD NOT LAST MORE THAN ONE OR TWO
HOURS AS THE BOUNDARY LAYER WARMS AND DEEPENS...LIFTING ANY CLOUD
BASES UP IN TO THE 035 TO 050 RANGE. THINK THAT AT LEAST A TEMPORARY
LOW CLOUD VFR CEILING WILL CONTINUE THROUGH THE AFTERNOON GIVEN
SUFFICIENT MOISTURE IN THE BOUNDARY LAYER. HAVE HELD ONTO A TWO HOUR
WINDOW OF THUNDERSTORMS PER THE 4KM WRF MODEL IN THE 21Z TO 23Z TIME
RANGE...BUT CONFIDENCE IS DROPPING. THE FRONT SHOULD FINALLY CROSS
THE REGION DURING THE MIDDLE PART OF THE EVENING WHICH WILL CLEAR
OUT THE LOW CLOUDS AND SHIFT THE WIND FROM SW TO NW...BY 04Z AT THE
LATEST. CONDITIONS SHOULD BE VFR FROM THAT POINT ONWARD. ON
FRIDAY...ONCE THE WINDS COME UP DURING MID MORNING...EXPECT FREQUENT
GUSTS FROM THE NW.
ELSEWHERE...SIMILAR CHANCES FOR MVFR CEILING UNTIL 20Z OR SO WHEN
THE BOUNDARY LAYER LIFTS THE CLOUD BASES ABOVE 030. OTHERWISE...
LESS OF A CHANCE FOR CONVECTIVE ACTIVITY. ONLY KHKY WARRANTS A
VICINITY THUNDERSTORM FOR THE TIME BEING. EXPECT VFR CONDITIONS
AFTER FRONTAL PASSAGE...WHICH SHOULD BE LATE AFTERNOON TO EARLY
EVENING. SOME UPSLOPE SHOWERS COULD OCCUR ALONG THE TN BORDER...BUT
THIS IS NOT EXPECTED TO AFFECT KAVL. WINDS SHOULD BE STRONG AND
GUSTY FROM THE NW ON FRIDAY.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 85% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% MED 79% HIGH 81% HIGH 95%
KHKY HIGH 89% HIGH 100% HIGH 83% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 94% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...PM
SHORT TERM...LG
LONG TERM...LG
AVIATION...PM
000
FXUS62 KCHS 231801
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
201 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION LATE TONIGHT...WITH DRY
HIGH PRESSURE BUILDING IN THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE DISTINCT SHORTWAVE PROGRESSING TOWARD THE FORECAST AREA FROM
THE WEST IS EVIDENT IN WATER VAPOR IMAGERY AS A NOTABLE BOUNDARY
BETWEEN DEEP MOISTURE OVER SOUTH CAROLINA/GEORGIA COASTAL AREAS
AND DRIER AIR FURTHER UPSTATE AND INLAND. THE MAIN COLD FRONT
ASSOCIATED WITH THE UPPER TROUGH AXIS IN THE OHIO VALLEY WILL
REMAIN TO THE NORTHWEST THROUGH THE DAYTIME HOURS...HOWEVER A PRE
FRONTAL TROUGH SEEN IN LATEST MESOANALYSIS WILL PROVIDE SOME
ADDITIONAL CONVERGENCE COINCIDENT WITH THE TIMING OF THE SHORTWAVE
ENERGY. THE ORIENTATION AND MOVEMENT OF THE SURFACE TROUGH HAS
SUPPORTED MORE SOLID DOWNSLOPE FLOW ACROSS THE GEORGIA
COUNTIES...WHILE SOUTH CAROLINA ZONES REMAIN WITHIN A MORE
SOUTHWEST FLOW FOR THE NEXT SEVERAL HOURS. THE DOWNSLOPE FLOW
ACROSS SOUTHERN LOCATIONS COULD LIMIT CONVECTIVE DEVELOPMENT LATER
TODAY.
SHOWERS CONTINUE TO DEVELOP ACROSS MAINLY CHARLESTON AND BERKELEY
COUNTIES...WHILE LATEST RADAR TRENDS ARE INDICATING ISOLATED SHOWERS
BEGINNING TO INITIATE WEST OF INTERSTATE 95 IN SOUTHEAST GEORGIA.
LATEST THINKING IS THAT SHOWERS/THUNDERSTORMS WILL CONTINUE OVER
THE TRI COUNTY...WITH ISOLATED CONVECTION SPREADING SOUTHWARD INTO
THE GEORGIA COASTAL ZONES ALONG THE SEABREEZE. HAVE INDICATED 30
PERCENT RAIN CHANCES IN THE FAVORED NORTHERN COASTAL AREAS THIS
AFTERNOON...WITH SLIGHT CHANCES INLAND SOUTH CAROLINA AND ALONG
THE GEORGIA COASTLINE. HAVE CAPPED RAIN CHANCES BELOW 15 PERCENT
FOR THE INLAND GEORGIA ZONES WHERE THE AFOREMENTIONED DOWNSLOPE
FLOW AND EARLIER INTRUSION OF DRIER AIR WILL SUPPRESS CONVECTIVE
DEVELOPMENT. MODIFYING THE CHS UPPER AIR SOUNDING FOR AFTERNOON
TEMPERATURES AND DEWPOINTS REVEALS ONLY MARGINAL INSTABILITY...AND
WITH CONTINUED WEAK LAPSE RATES AND WIND PROFILES...SEVERE
POTENTIAL IS LOW AGAIN TODAY.
STRATOCUMULUS QUICKLY DEVELOPED ACROSS SOUTH CENTRAL GEORGIA AND
HAS SHIFTED INTO THE CLEAR AREAS OF SOUTHEAST GEORGIA BY EARLY
AFTERNOON. AS A RESULT...MOST OF THE FORECAST AREA WILL REMAIN
PARTLY CLOUDY TO MOSTLY CLOUDY THROUGHOUT THE AFTERNOON
HOURS...WITH THICKEST SKY COVER ACROSS THE NORTHERN ZONES. CURRENT
FORECAST TEMPERATURES ARE IN DECENT AGREEMENT WITH LATEST
TEMPERATURES...AND WILL THUS MAINTAIN ONGOING FORECAST HIGHS
RANGING FROM THE UPPER 80S INLAND TO THE LOW TO MID 80S ALONG THE
COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE COLD FRONT WILL MOVE THROUGH SHORTLY AFTER MIDNIGHT TONIGHT
WITH SLIGHTLY DRIER AIR BEGINNING TO FILTER INTO THE REGION.
MOSTLY CLEAR SKIES EXPECTED WITH TEMPERATURES IN THE LOWER 60S.
FRIDAY AND FRIDAY NIGHT...AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE
MID-ATLANTIC REGION ON FRIDAY. IN WAKE OF THE DEPARTING COLD
FRONT...A DEEP LAYERED NORTHWEST FLOW WILL PREVAIL THROUGH MUCH OF
THE DAY. THE DOWNSLOPE FLOW WILL RESULT IN DRYING ACROSS THE AREA
AND WILL ALSO NEGATE MOST OF THE INITIAL SURGE OF COLD AIR ADVECTION
AS HIGHS SHOULD STILL BE IN THE MID TO UPPER 80S. UNDER MOSTLY SUNNY
SKIES...BREEZY CONDITIONS ARE ALSO EXPECTED. THEN...AS THE UPPER
TROUGH PASSES OFF THE MID-ATLANTIC COAST FRIDAY EVENING...IT WILL
PUSH A SECONDARY COLD FRONT ACROSS THE AREA ALLOWING HIGH PRESSURE
TO BUILD FROM THE GREAT LAKES REGION. THE AIR MASS WILL BEGIN TO
MODIFY SIGNIFICANTLY FOLLOWING THE SECONDARY COLD FRONT WITH
TEMPERATURES PLUMMETING INTO THE UPPER 40S AND LOWER 50S FRIDAY
NIGHT ON A NORTHERLY FLOW.
SATURDAY AND SATURDAY NIGHT...A VERY DRY AIR MASS WILL SETTLE OVER
THE REGION SATURDAY AS HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
GREAT LAKES REGION. PRECIPITABLE WATER VALUES OF .25 TO .40 INCHES
WILL BE ABOUT AS LOW AS THEY CAN GET FOR THIS TIME OF YEAR...OR MORE
THAN 2 STANDARD DEVIATIONS BELOW NORMAL. FORECAST THICKNESS VALUES
ONLY SUPPORT HIGHS IN THE MID TO UPPER 70S...BUT GIVEN FULL SUNSHINE
AND THE HIGHER SUN ANGLE THIS TIME OF YEAR...WILL INDICATE HIGHS IN
THE UPPER 70S TO LOWER 80S ACROSS THE AREA. ANOTHER UNSEASONABLY
COOL NIGHT IS EXPECTED SATURDAY NIGHT...WITH LOWS IN THE LOWER TO
MID 50S.
SUNDAY...A WEAK PRESSURE PATTERN WILL PREVAIL OVER THE REGION. AN
INCREASE IN MID AND HIGH LEVEL MOISTURE WILL SUPPORT SOME CLOUD
COVER BUT THE AIR MASS IS TOO DRY STILL FOR ANY SHOWERS TO DEVELOP.
HIGHS SHOULD BE IN THE LOWER TO MID 80S ACROSS MUCH OF THE AREA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE REGION WILL BE SANDWICHED BETWEEN TWO AREAS OF HIGH PRESSURE
EARLY IN THE WEEK...THE STRONGER OF THE TWO PASSING ACROSS THE
MID-ATLANTIC REGION AND THE OTHER OVER THE NORTHEAST GULF OF MEXICO.
DEEPENING MOISTURE WILL RESULT IN AT LEAST AN INCREASE IN CLOUD
COVER...BUT IT APPEARS THE RAIN-FREE CONDITIONS SHOULD PERSIST
THROUGH MEMORIAL DAY. ATLANTIC HIGH PRESSURE WILL THEN BECOME
ESTABLISHED THROUGH THE MIDDLE OF NEXT WEEK...SUPPORTING MAINLY
DIURNAL ISOLATED CONVECTION EACH AFTERNOON ALONG AND AHEAD OF THE
SEA BREEZE TUESDAY THROUGH THURSDAY. TEMPERATURES WILL MODERATE TO
NEAR NORMAL BY EARLY NEXT WEEK AND CONTINUE NEAR SEASONAL NORMS
THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT BOTH KCHS AND KSAV THROUGH 18Z
FRIDAY. SCATTERED SHOWERS HAVE ALREADY DEVELOPED IN ASSOCIATION
WITH A PRE-FRONTAL TROUGH ACROSS SOUTHEAST SOUTH CAROLINA...WITH
EVIDENCE OF ISOLATED ACTIVITY ALSO INITIATING ALONG THE SEABREEZE
WEST OF INTERSTATE 95 IN SOUTHEAST GEORGIA. AT THIS
POINT...CONFIDENCE IN COVERAGE NEAR KSAV IS TOO LOW TO MENTION IN
THE TAF FOR THIS AFTERNOON. WILL INCLUDE VCSH AT KCHS FOR THE
NEXT FEW HOURS DUE TO THE ACTIVITY TO THE EAST. WILL CONTINUE TO
MONITOR RADAR TRENDS IN CASE AMENDMENTS ARE NEEDED IF CONVECTION
NEARS THE TERMINALS. EXPECT ANY SHOWERS/THUNDERSTORMS TO DIMINISH
AND SKIES TO BEGIN CLEARING THIS EVENING. A COLD FRONT PROGRESSING
THROUGH THE REGION OVERNIGHT WILL SUPPORT STEADILY VEERING
WINDS...WITH NORTHWEST FLOW EXPECTED BY DAYBREAK FRIDAY.
EXTENDED AVIATION...VFR CONDITIONS WILL PREVAIL. GUSTY WINDS ARE
POSSIBLE FRIDAY AFTERNOON.
&&
.MARINE...
WINDS AND SEAS WILL BE FAIRLY BENIGN TODAY...BEFORE WINDS
INCREASE OUT OF THE SOUTHWEST AND WEST TONIGHT AS A COLD FRONT
PUSHES THROUGH THE WATERS. WIND SPEEDS WILL INCREASE TO AROUND 15
KT...YET THE OFFSHORE FETCH WILL LIMIT THE BUILDING OF SEAS TO NO
HIGHER THAN 4 FT.
FRIDAY THROUGH TUESDAY...A NORTHWEST FLOW WILL DEVELOP ON FRIDAY IN
WAKE OF A DEPARTING COLD FRONT. A SECONDARY COLD FRONT WILL THEN
MOVE THROUGH BY FRIDAY EVENING...WITH A STRONGER NORTHERLY SURGE
DEVELOPING IN ITS WAKE FRIDAY NIGHT INTO EARLY SATURDAY...POSSIBLY
RESULTING IN SMALL CRAFT ADVISORY CONDITIONS OVER A PORTION OF THE
WATERS.
CONDITIONS WILL THEN IMPROVE LATER IN THE WEEKEND WITH WINDS/SEAS
EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH
EARLY NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...JAQ/JRL
LONG TERM...JAQ
AVIATION...WMS
MARINE...JAQ/JRL
TIDES/COASTAL FLOODING...
000
FXUS62 KGSP 231758
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
158 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SWING THROUGH THE REGION TOMORROW...
BRINGING COOLER AND DRIER CONDITIONS FOR THE WEEKEND. TEMPERATURES
WILL MODERATE BY THE BEGINNING OF NEXT WEEK... WITH A CHANCE OF
AFTERNOON SHOWERS AND THUNDERSTORMS EACH DAY CONCENTRATED OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF EARLY AFTERNOON...MOST OF THE CONVECTIVE DEVELOPMENT HAS TAKEN
PLACE JUST EAST OF THE CLT METRO AREA. OTHERWISE...KGSP RADAR IS
NEARLY QUIET ACROSS THE FCST AREA. SEEING SOME ENHANCEMENT TO THE CU
NEAR THE BLUE RIDGE...SO AM NOT READY TO GIVE UP ON THE PRECIP
CHANCES FOR THE AFTERNOON...PER THE OLD RUN OF THE 4KM WRF. TEMPS
LOOK OKAY.
PREVIOUS DISCUSSION...
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 145 PM THURSDAY...THE 06Z GFS AND 00Z ECMWF ARE NOW SOMEWHAT
AT ODDS IN REGARD TO THE UPPER LEVEL FLOW PATTERN. THE MAIN
DIFFERENCE IS THAT THE GFS IS QUICKER MOVING THE ANOMOLOUSLY STRONG
UPPER LOW THROUGH NEW ENGLAND AND OUT OF THE PICTURE. THIS ALLOWS
THE FLOW TO DEAMPLIFY OVER THE SE BY MONDAY WITH AN UPPER RIDGE
BUILDING OVER THE REGION BY MIDWEEK. THE ECM ON THE OTHER HAND KEEPS
THE SE U.S. IN A NW FLOW REGIME TO THE EAST OF AN UPPER HIGH IT
BUILDS OVER THE LOWER MISSISSIPPI VALLEY. THIS ALLOWS WEAK IMPULSES
TO TRANSLATE ACROSS THE REGION IN THE NW FLOW MAKING FOR A RATHER
UNSETTLED PERIOD UNTIL LATE WEEK WHEN THE ECM FINALLY BUILDS THE
RIDGE TO THE EAST. THE LATEST GFS ENSEMBLE SUPPORTS THE GFS
OPERATIONAL RUN.
HPC HAS FAVORED THE ECM IN ITS MEDIUM RANGE. HOWEVER...I HAVE HEDGED
THE FORECAST TOWARD A BLEND OF OUR OFFICIAL/GFS/ECM WHICH WOULD PUT
A DIURNAL HARMONIC TO THE FORECAST FAVORING SCATTERED AFTERNOON
CONVECTION MAINLY OVER THE MOUNTAINS. THE EXCEPTION IS MON AFTERNOON
WHEN SOME SCATTERED SHOWERS/THUNDERSTORMS MAY ALSO OCCUR OVER THE NC
FOOTHILLS/PIEDMONT AS THE BACKDOOR FRONT THAT SLIPPED THROUGH THE
AREA ON SUN RETURNS NORTH AS A WARM FRONT. TEMPS WILL BEGIN THE
PERIOD A LITTLE BELOW CLIMO...THEN WARM TO ABOUT A CATEGORY ABOVE
CLIMO BY THE END OF THE WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...MVFR CIG RESTRICTION SHOULD NOT LAST MORE THAN ONE OR TWO
HOURS AS THE BOUNDARY LAYER WARMS AND DEEPENS...LIFTING ANY CLOUD
BASES UP IN TO THE 035 TO 050 RANGE. THINK THAT AT LEAST A TEMPORARY
LOW CLOUD VFR CEILING WILL CONTINUE THROUGH THE AFTERNOON GIVEN
SUFFICIENT MOISTURE IN THE BOUNDARY LAYER. HAVE HELD ONTO A TWO HOUR
WINDOW OF THUNDERSTORMS PER THE 4KM WRF MODEL IN THE 21Z TO 23Z TIME
RANGE...BUT CONFIDENCE IS DROPPING. THE FRONT SHOULD FINALLY CROSS
THE REGION DURING THE MIDDLE PART OF THE EVENING WHICH WILL CLEAR
OUT THE LOW CLOUDS AND SHIFT THE WIND FROM SW TO NW...BY 04Z AT THE
LATEST. CONDITIONS SHOULD BE VFR FROM THAT POINT ONWARD. ON
FRIDAY...ONCE THE WINDS COME UP DURING MID MORNING...EXPECT FREQUENT
GUSTS FROM THE NW.
ELSEWHERE...SIMILAR CHANCES FOR MVFR CEILING UNTIL 20Z OR SO WHEN
THE BOUNDARY LAYER LIFTS THE CLOUD BASES ABOVE 030. OTHERWISE...
LESS OF A CHANCE FOR CONVECTIVE ACTIVITY. ONLY KHKY WARRANTS A
VICINITY THUNDERSTORM FOR THE TIME BEING. EXPECT VFR CONDITIONS
AFTER FRONTAL PASSAGE...WHICH SHOULD BE LATE AFTERNOON TO EARLY
EVENING. SOME UPSLOPE SHOWERS COULD OCCUR ALONG THE TN BORDER...BUT
THIS IS NOT EXPECTED TO AFFECT KAVL. WINDS SHOULD BE STRONG AND
GUSTY FROM THE NW ON FRIDAY.
OUTLOOK...VFR THROUGH THE PERIOD.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 85% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% MED 79% HIGH 81% HIGH 95%
KHKY HIGH 89% HIGH 100% HIGH 83% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 94% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...JAT/PM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...PM
000
FXUS62 KCAE 231750
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
150 PM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...MODEL FORECAST SOUNDINGS SHOW A CONDITIONALLY
UNSTABLE AIRMASS WITH A WEAK MID LEVEL CAP. MODELS GIVE AFTERNOON
CAPES 1000-2000 J/KG...LIS -5/-6 AND TOTALS AROUND 45. PW VALUES
INITIALLY AROUND 1.4 INCHES BUT DRIER AIR WORKS IN FROM WEST TO
LOWER PW TO 1.20 INCHES. KIS LESS THAN 30 AS MOISTURE IS MAINLY
BELOW 10 KFT. HOWEVER...AFTERNOON HEATING MAY LIFT MOISTURE ENOUGH
FOR A FEW THUNDERSTORMS MAINLY IN THE EAST PART. SPC HAS AREA IN
GENERAL THUNDERSTORMS OUTLOOK BUT IF HIGH ELEVATED CORES DEVELOP
THE POTENTIAL EXISTS FOR PERHAPS ISOLATED STRONG TO SEVERE STORMS
BUT AGAIN MAINLY IN THE EAST. HAVE MAINLY 20-30 PERCENT CHANCE BUT
IN FAR EAST AND NORTHEAST WILL KEEP 40-60 PERCENT CHANCE. HIGH
TEMPERATURES IN THE MID TO UPPER 80S.
TONIGHT...A 20 PERCENT CHANCE IN THE EAST DURING THE EVENING.
PLAN ON NO POPS IN THE WEST AS DRIER AIR MOVES IN FROM THE WEST
WITH THE COLD FRONT. LOWS UPPER 50S TO LOWER 60S.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
DRYING BEHIND THE FRONT SHOULD DOMINATE FRIDAY THROUGH FRIDAY
NIGHT. MIXING ASSOCIATED WITH THE FRONT SUPPORTED THE WARMER
TEMPERATURE GUIDANCE TONIGHT. HIGH PRESSURE WILL BRING COOLER
DRIER CONDITIONS FRIDAY NIGHT AND SATURDAY. WILL GO WITH GFS MOS
GUIDANCE IN THE MID 40S FRIDAY NIGHT AND MODEL BLEND UPPER 70S
TO LOWER 80S SATURDAY. AIRMASS MODIFIES BY SATURDAY NIGHT WITH
LOWS IN THE LOWER 50S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MEDIUM RANGE MODELS IN GOOD AGREEMENT WITH UPPER RIDGE WORKING
IN FROM THE WEST. BOTH MODELS SHOW A WEAK SURFACE FRONTAL BOUNDARY
WHICH REMAINS MAINLY TO THE NORTH BUT ECMWF SHOWS THE FRONT A
LITTLE BIT STRONGER THAN THE GFS. THE ECMWF ALSO KEEPS THE FRONT
A LITTLE FARTHER TO THE SOUTH. DRY TO START SUNDAY AND MONDAY BUT
BY THE END OF THE EXTENDED PERIOD...THE AIRMASS MOISTURE INCREASES
AND THE INSTABILITY INCREASES. EXPECT MORE DIURNAL SHOWERS AND
THUNDERSTORMS TUESDAY THROUGH THURSDAY. HIGH TEMPERATURES INCREASE
FROM THE LOWER 80S SUNDAY TO THE MID 80S MONDAY AND TUESDAY TO
THE UPPER 80S BY THURSDAY. OVERNIGHT LOW TEMPERATURES ARE EXPECTED
TO BE IN THE UPPER 50S SUNDAY NIGHT BUT INCREASE TO THE LOWER 60S
FOR THE REST OF THE PERIOD.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SATELLITE SHOWS PLENTY OF SC/CU AROUND THIS EARLY AFTERNOON. MOST
TAF SITES HAVE RETURNED TO VFR CONDITIONS...EXCEPT BOTH AGS/DNL
REPORTING MVFR CONDITIONS. EXPECT WITH ADDITIONAL DAYTIME HEATING
THAT CLOUD BASIS WILL RISE BETWEEN 19Z TO 20Z AND VFR CONDITIONS
WILL RETURN. AT THIS TIME...CONVECTION APPEARS TO BE MAINLY
CONCENTRATED ACROSS THE NORTHERN MIDLANDS/PEE DEE AND ALONG THE
COAST. THIS IS IN GOOD AGREEMENT WITH LOCAL/SPC WRF MODEL RUNS. WILL
CONTINUE WITH VFR CONDITIONS THROUGH THE PERIOD. WITH PASSAGE OF
COLD FRONT LATE THIS EVENING/OVERNIGHT...MODELS INDICATE A 30 KT LOW
LEVEL JET. THIS WILL KEEP WINDS UP SLIGHTLY OVERNIGHT BEFORE
BECOMING MORE BREEZE ON FRIDAY. ON FRIDAY...WINDS WILL BE FROM THE
NORTHWEST BEHIND THE FRONT AND BREEZY WITH WINDS AVERAGE 10 TO 15
KTS WITH GUSTS UP TO 25 KTS AT TIMES.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 231517
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1117 AM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION LATE TONIGHT...WITH DRY
HIGH PRESSURE BUILDING IN THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE DISTINCT SHORTWAVE PROGRESSING TOWARD THE FORECAST AREA FROM
THE WEST IS EVIDENT IN WATER VAPOR IMAGERY AS A NOTABLE BOUNDARY
BETWEEN DEEP MOISTURE OVER SOUTH CAROLINA/GEORGIA COASTAL AREAS
AND DRIER AIR FURTHER UPSTATE AND INLAND. THE MAIN COLD FRONT
ASSOCIATED WITH THE UPPER TROUGH AXIS IN THE OHIO VALLEY WILL
REMAIN TO THE NORTHWEST THROUGH THE DAYTIME HOURS...HOWEVER A PRE
FRONTAL TROUGH SEEN IN LATEST MESOANALYSIS WILL PROVIDE SOME
ADDITIONAL CONVERGENCE COINCIDENT WITH THE TIMING OF THE SHORTWAVE
ENERGY THIS AFTERNOON. THE ORIENTATION AND MOVEMENT OF THE
SURFACE TROUGH WILL SUPPORT MORE SOLID DOWNSLOPE FLOW ACROSS THE
GEORGIA COUNTIES...WHILE SOUTH CAROLINA ZONES REMAIN WITHIN A MORE
SOUTHWEST FLOW FOR THE NEXT SEVERAL HOURS. THE DOWNSLOPE FLOW
ACROSS SOUTHERN LOCATIONS COULD LIMIT CONVECTIVE DEVELOPMENT LATER
TODAY.
RADAR TRENDS CONFIRM THAT INITIAL CONVECTIVE DEVELOPMENT WILL
OCCUR ACROSS THE SOUTH CAROLINA ZONES...AS ISOLATED SHOWER
ACTIVITY IS ALREADY TRACKING ACROSS THE CHARLESTON TRI COUNTY
REGION. LATEST THINKING IS THAT SHOWERS/THUNDERSTORMS WILL
INCREASE IN COVERAGE OVER THE TRI COUNTY...WITH ISOLATED
CONVECTION SPREADING SOUTHWARD INTO THE GEORGIA COASTAL ZONES
ALONG THE SEABREEZE. HAVE INDICATED 30 PERCENT RAIN CHANCES IN THE
FAVORED NORTHERN COASTAL AREAS THIS AFTERNOON...WITH SLIGHT
CHANCES INLAND SOUTH CAROLINA AND ALONG THE GEORGIA COASTLINE.
HAVE CAPPED RAIN CHANCES BELOW 15 PERCENT FOR THE INLAND GEORGIA
ZONES WHERE THE AFOREMENTIONED DOWNSLOPE FLOW AND EARLIER
INTRUSION OF DRIER AIR WILL SUPPRESS CONVECTIVE DEVELOPMENT.
MODIFYING THE CHS UPPER AIR SOUNDING FOR AFTERNOON TEMPERATURES
AND DEWPOINTS REVEALS ONLY MARGINAL INSTABILITY...AND WITH
CONTINUED WEAK LAPSE RATES AND WIND PROFILES...SEVERE POTENTIAL IS
LOW AGAIN TODAY.
STRATOCUMULUS QUICKLY DEVELOPED ACROSS SOUTH CENTRAL GEORGIA AND
IS SHIFTING INTO THE CLEAR AREAS OF SOUTHEAST GEORGIA BY MID
MORNING. AS A RESULT...MOST OF THE FORECAST AREA WILL REMAIN
PARTLY CLOUDY TO MOSTLY CLOUDY THROUGHOUT THE AFTERNOON
HOURS...WITH THICKEST SKY COVER ACROSS THE NORTHERN ZONES. CURRENT
FORECAST TEMPERATURES ARE IN DECENT AGREEMENT WITH LATEST
TEMPERATURES...AND WILL THUS MAINTAIN ONGOING FORECAST HIGHS
RANGING FROM THE UPPER 80S INLAND TO THE LOW TO MID 80S ALONG THE
COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE COLD FRONT WILL MOVE THROUGH SHORTLY AFTER MIDNIGHT TONIGHT
WITH SLIGHTLY DRIER AIR BEGINNING TO FILTER INTO THE REGION.
MOSTLY CLEAR SKIES EXPECTED WITH TEMPERATURES IN THE LOWER 60S.
FRIDAY AND FRIDAY NIGHT...AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE
MID-ATLANTIC REGION ON FRIDAY. IN WAKE OF THE DEPARTING COLD
FRONT...A DEEP LAYERED NORTHWEST FLOW WILL PREVAIL THROUGH MUCH OF
THE DAY. THE DOWNSLOPE FLOW WILL RESULT IN DRYING ACROSS THE AREA
AND WILL ALSO NEGATE MOST OF THE INITIAL SURGE OF COLD AIR ADVECTION
AS HIGHS SHOULD STILL BE IN THE MID TO UPPER 80S. UNDER MOSTLY SUNNY
SKIES...BREEZY CONDITIONS ARE ALSO EXPECTED. THEN...AS THE UPPER
TROUGH PASSES OFF THE MID-ATLANTIC COAST FRIDAY EVENING...IT WILL
PUSH A SECONDARY COLD FRONT ACROSS THE AREA ALLOWING HIGH PRESSURE
TO BUILD FROM THE GREAT LAKES REGION. THE AIR MASS WILL BEGIN TO
MODIFY SIGNIFICANTLY FOLLOWING THE SECONDARY COLD FRONT WITH
TEMPERATURES PLUMMETING INTO THE UPPER 40S AND LOWER 50S FRIDAY
NIGHT ON A NORTHERLY FLOW.
SATURDAY AND SATURDAY NIGHT...A VERY DRY AIR MASS WILL SETTLE OVER
THE REGION SATURDAY AS HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
GREAT LAKES REGION. PRECIPITABLE WATER VALUES OF .25 TO .40 INCHES
WILL BE ABOUT AS LOW AS THEY CAN GET FOR THIS TIME OF YEAR...OR MORE
THAN 2 STANDARD DEVIATIONS BELOW NORMAL. FORECAST THICKNESS VALUES
ONLY SUPPORT HIGHS IN THE MID TO UPPER 70S...BUT GIVEN FULL SUNSHINE
AND THE HIGHER SUN ANGLE THIS TIME OF YEAR...WILL INDICATE HIGHS IN
THE UPPER 70S TO LOWER 80S ACROSS THE AREA. ANOTHER UNSEASONABLY
COOL NIGHT IS EXPECTED SATURDAY NIGHT...WITH LOWS IN THE LOWER TO
MID 50S.
SUNDAY...A WEAK PRESSURE PATTERN WILL PREVAIL OVER THE REGION. AN
INCREASE IN MID AND HIGH LEVEL MOISTURE WILL SUPPORT SOME CLOUD
COVER BUT THE AIR MASS IS TOO DRY STILL FOR ANY SHOWERS TO DEVELOP.
HIGHS SHOULD BE IN THE LOWER TO MID 80S ACROSS MUCH OF THE AREA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE REGION WILL BE SANDWICHED BETWEEN TWO AREAS OF HIGH PRESSURE
EARLY IN THE WEEK...THE STRONGER OF THE TWO PASSING ACROSS THE
MID-ATLANTIC REGION AND THE OTHER OVER THE NORTHEAST GULF OF MEXICO.
DEEPENING MOISTURE WILL RESULT IN AT LEAST AN INCREASE IN CLOUD
COVER...BUT IT APPEARS THE RAIN-FREE CONDITIONS SHOULD PERSIST
THROUGH MEMORIAL DAY. ATLANTIC HIGH PRESSURE WILL THEN BECOME
ESTABLISHED THROUGH THE MIDDLE OF NEXT WEEK...SUPPORTING MAINLY
DIURNAL ISOLATED CONVECTION EACH AFTERNOON ALONG AND AHEAD OF THE
SEA BREEZE TUESDAY THROUGH THURSDAY. TEMPERATURES WILL MODERATE TO
NEAR NORMAL BY EARLY NEXT WEEK AND CONTINUE NEAR SEASONAL NORMS
THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KCHS AND KSAV
THROUGH 12Z FRIDAY. SCATTERED SHOWERS HAVE ALREADY DEVELOPED IN
ASSOCIATION WITH A PRE-FRONTAL TROUGH ACROSS SOUTHEAST SOUTH
CAROLINA. HAVE KEPT MENTION OF ANY PRECIPITATION OUT OF THE KSAV
TAF SINCE COVERAGE WILL BE LIMITED ACROSS SOUTHEAST GEORGIA. ANY
CEILINGS WILL REMAIN VFR OUTSIDE OF CONVECTION...WITH CLEARING
EXPECTED TONIGHT.
EXTENDED AVIATION...VFR CONDITIONS WILL PREVAIL. GUSTY WINDS ARE
POSSIBLE FRIDAY AFTERNOON.
&&
.MARINE...
WINDS AND SEAS WILL BE FAIRLY BENIGN TODAY...BEFORE WINDS
INCREASE OUT OF THE SOUTHWEST AND WEST TONIGHT AS A COLD FRONT
PUSHES THROUGH THE WATERS. WIND SPEEDS WILL INCREASE TO AROUND 15
KT...YET THE OFFSHORE FETCH WILL LIMIT THE BUILDING OF SEAS TO NO
HIGHER THAN 4 FT.
FRIDAY THROUGH TUESDAY...A NORTHWEST FLOW WILL DEVELOP ON FRIDAY IN
WAKE OF A DEPARTING COLD FRONT. A SECONDARY COLD FRONT WILL THEN
MOVE THROUGH BY FRIDAY EVENING...WITH A STRONGER NORTHERLY SURGE
DEVELOPING IN ITS WAKE FRIDAY NIGHT INTO EARLY SATURDAY...POSSIBLY
RESULTING IN SMALL CRAFT ADVISORY CONDITIONS OVER A PORTION OF THE
WATERS.
CONDITIONS WILL THEN IMPROVE LATER IN THE WEEKEND WITH WINDS/SEAS
EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH
EARLY NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...WMS
SHORT TERM...JAQ/JRL
LONG TERM...JAQ
AVIATION...JAQ
MARINE...JAQ/JRL
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 231439
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1039 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE AND INSTABILITY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH
WAS SUPPORTING SCATTERED SHOWERS EARLY THIS MORNING. SATELLITE
TRENDS AND THE MODELS INDICATE DEEPER MOISTURE ASSOCIATED WITH
THE SHORTWAVE TROUGH WILL SHIFT EAST OF THE FORECAST AREA EARLY
THIS AFTERNOON. A PRE-FRONTAL TROUGH WILL BE IN THE FORECAST AREA
THROUGH TODAY. CONVERGENCE ASSOCIATED WITH THIS FEATURE PLUS
DIURNAL HEATING SHOULD SUPPORT THUNDERSTORMS BUT EXPECT LIMITED
COVERAGE BECAUSE OF DIMINISHED MOISTURE BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS AFTERNOON. MAINTAINED CHANCE POPS WITH
THE GREATER VALUES IN THE NORTHEAST PART CLOSER TO THE DEEPER
MOISTURE AND MORE CONVERGENCE ASSOCIATED WITH THE SURFACE TROUGH.
BASICALLY HAVE 20-30 PERCENT CHANCE WEST AND 30-50 PERCENT CHANCE
EAST WITH AROUND 50 PERCENT CHANCE IN THE NORTHEAST PART. MODERATE
INSTABILITY MAY SUPPORT DAMAGING WIND WITH A FEW OF THE
THUNDERSTORMS. WET-BULB ZERO HEIGHTS ALSO SUPPORT HAIL. THE
TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
CONVERGENCE ASSOCIATED WITH THE COLD FRONT MAY SUPPORT
THUNDERSTORMS EARLY. COVERAGE SHOULD STILL BE LIMITED WITH DEEPER
MOISTURE EAST OF THE AREA. DRYING BEHIND THE FRONT SHOULD DOMINATE
LATE TONIGHT THROUGH FRIDAY NIGHT. MIXING ASSOCIATED WITH THE
FRONT SUPPORTED THE WARMER TEMPERATURE GUIDANCE TONIGHT. WE WILL
GET OFF TO A RELATIVELY WARM START SO THE WARMER GUIDANCE APPEARED
BETTER FRIDAY. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FRIDAY NIGHT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. EXPECT SOME INCREASE IN MOISTURE BEGINNING MONDAY. THE
GFS AND ECMWF DISPLAY A WARM FRONT DEVELOPING NEAR THE AREA. THE
GFS IS FARTHER NORTHWARD WITH THE PLACEMENT OF THE FRONT. THE GFS
ALSO SHOWS LESS MOISTURE IN THE FORECAST AREA. BOTH MODELS SHOW
AN INCREASE IN H5 RIDGING WHICH SHOULD LIMIT THUNDERSTORMS.
BELIEVE THE BEST FORECAST FOR NOW IS AN AVERAGE OF THE GFS AND
ECMWF MOS. FORECASTED SLIGHT CHANCE POPS TUESDAY AND WEDNESDAY.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
EARLY MORNING CONVECTION AS NEARLY DIMINISHED ACROSS THE CWA THIS
MORNING. SOME MVFR CIGS WILL LINGER UNTIL AROUND 14Z. UPPER IMPULSE
AND SURFACE TROUGH WILL MOVE THROUGH THIS AFTERNOON...POSSIBLY
LEADING TO SCT SHRA/TSRA. BEST CHANCE APPEARS TO BE NORTH/EAST OF
MOST TAF SITES. DUE TO THE SCATTERED NATURE OF THE CONVECTION...WILL
NOT MENTION PRECIPITATION AT ANY OF THE TAF SITES FOR THE AFTERNOON
HOURS. BY LATER THIS EVENING...SKIES SHOULD BEGIN TO CLEAR AS DRIER
AIR MOVES INTO THE AREA FROM THE WEST.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 231340
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
940 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF MID MORNING...THE KGSP RADAR SHOWED A PATCH OF VERY LIGHT RAIN
MOVING ACROSS METRO CLT AND SOME OTHER SHOWER ACTIVITY SKIRTING THE
NRN MOUNTAINS. THE POP FOR THE NEXT HOUR OR TWO WAS ADJUSTED
ACCORDINGLY. AS FOR THE REST OF THE DAY...THE LATEST RUNS OF THE
CONVECTION ALLOWING MODELS ARE NOT AS EXCITED COMPARED TO YESTERDAY.
THINK THE MOST LIKELY SCENARIO WILL BE FOR SCATTERED SHOWERS
DEVELOPING OVER THE PIEDMONT DURING THE MIDDLE PART OF THE DAY AND
THEN MOVING OFF TO THE EAST BEFORE BECOMING MORE NUMEROUS. THESE
MODELS WERE VERY GOOD YESTERDAY. WITH THAT IN MIND...HAVE LOWERED
THE EXPECTATIONS FOR THIS AFTERNOON AND TRIMMED POP BACK TO THE
CHANCE RANGE ACROSS ALL BUT THE NORTHERNMOST ZONES. TEMP TRENDS WERE
ALSO ADJUSTED DOWNWARD FOR THE MORNING BECAUSE OF THE EXTENSIVE
CONVECTIVE DEBRIS CLOUDS.
PREVIOUS DISCUSSION...
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AT KCLT...MVFR CIG RESTRICTION HAS FINALLY DEVELOPED AND WILL BE
CARRIED INITIALLY. THE LATEST GUIDANCE SUPPORTS VFR...SO THE
RESTRICTION WILL ONLY BE TEMPORARY FOR NOW. SW WINDS WILL APPROACH
10 KNOTS THIS MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE
RESTRICTIONS IS EXPECTED THIS AFTERNOON AS A COLD FRONT MOVES
THROUGH FROM THE W... AND ANOTHER APPROACHES FROM THE NW. CONVECTION
WILL MOVE OFF TO THE EAST BY THIS EVENING....WHILE SW WINDS VEER TO
NW AND BECOME GUSTY. MODEL TIME HEIGHTS SUGGEST THE A LOW VFR CIG
WILL PERSIST INTO THIS EVENING.
ELSEWHERE...RESTRICTIONS WILL END BY MID MORNING AS WINDS COME UP
FROM THE SW IN THE FOOTHILLS AND NW IN THE MOUNTAINS. ADDITIONAL
CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY BETWEEN A
DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING FROM THE
NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE FOOTHILLS AND
BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE EVENING.
OVERNIGHT PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
BORDERING TN THIS EVENING IN NW UPSLOPE FLOW.
OUTLOOK...VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-13Z
KCLT HIGH 97% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 95% HIGH 100% HIGH 95% MED 79%
KHKY HIGH 88% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 97% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...JAT/PM
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KCAE 231313
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
913 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE AND INSTABILITY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH
WAS SUPPORTING SCATTERED SHOWERS EARLY THIS MORNING. SATELLITE
TRENDS AND THE MODELS INDICATE DEEPER MOISTURE ASSOCIATED WITH
THE SHORTWAVE TROUGH WILL SHIFT EAST OF THE FORECAST AREA EARLY
THIS AFTERNOON. A PRE-FRONTAL TROUGH WILL BE IN THE FORECAST AREA
THROUGH TODAY. CONVERGENCE ASSOCIATED WITH THIS FEATURE PLUS
DIURNAL HEATING SHOULD SUPPORT THUNDERSTORMS BUT EXPECT LIMITED
COVERAGE BECAUSE OF DIMINISHED MOISTURE BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS AFTERNOON. MAINTAINED CHANCE POPS WITH
THE GREATER VALUES IN THE NORTHEAST PART CLOSER TO THE DEEPER
MOISTURE AND MORE CONVERGENCE ASSOCIATED WITH THE SURFACE TROUGH.
MODERATE INSTABILITY MAY SUPPORT DAMAGING WIND WITH A FEW OF THE
THUNDERSTORMS. WET-BULB ZERO HEIGHTS ALSO SUPPORT HAIL. THE
TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
CONVERGENCE ASSOCIATED WITH THE COLD FRONT MAY SUPPORT
THUNDERSTORMS EARLY. COVERAGE SHOULD STILL BE LIMITED WITH DEEPER
MOISTURE EAST OF THE AREA. DRYING BEHIND THE FRONT SHOULD DOMINATE
LATE TONIGHT THROUGH FRIDAY NIGHT. MIXING ASSOCIATED WITH THE
FRONT SUPPORTED THE WARMER TEMPERATURE GUIDANCE TONIGHT. WE WILL
GET OFF TO A RELATIVELY WARM START SO THE WARMER GUIDANCE APPEARED
BETTER FRIDAY. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FRIDAY NIGHT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. EXPECT SOME INCREASE IN MOISTURE BEGINNING MONDAY. THE
GFS AND ECMWF DISPLAY A WARM FRONT DEVELOPING NEAR THE AREA. THE
GFS IS FARTHER NORTHWARD WITH THE PLACEMENT OF THE FRONT. THE GFS
ALSO SHOWS LESS MOISTURE IN THE FORECAST AREA. BOTH MODELS SHOW
AN INCREASE IN H5 RIDGING WHICH SHOULD LIMIT THUNDERSTORMS.
BELIEVE THE BEST FORECAST FOR NOW IS AN AVERAGE OF THE GFS AND
ECMWF MOS. FORECASTED SLIGHT CHANCE POPS TUESDAY AND WEDNESDAY.
&&
.AVIATION /13Z THURSDAY THROUGH TUESDAY/...
EARLY MORNING CONVECTION AS NEARLY DIMINISHED ACROSS THE CWA THIS
MORNING. SOME MVFR CIGS WILL LINGER UNTIL AROUND 14Z. UPPER IMPULSE
AND SURFACE TROUGH WILL MOVE THROUGH THIS AFTERNOON...POSSIBLY
LEADING TO SCT SHRA/TSRA. BEST CHANCE APPEARS TO BE NORTH/EAST OF
MOST TAF SITES. DUE TO THE SCATTERED NATURE OF THE CONVECTION...WILL
NOT MENTION PRECIPITATION AT ANY OF THE TAF SITES FOR THE AFTERNOON
HOURS. BY LATER THIS EVENING...SKIES SHOULD BEGIN TO CLEAR AS DRIER
AIR MOVES INTO THE AREA FROM THE WEST.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 231155
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
755 AM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH LATE TONIGHT WITH DRY HIGH PRESSURE
BUILDING IN THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RAIN SHOWERS ASSOCIATED WITH A WELL DEFINED SHORTWAVE DISTURBANCE
MOVING ACROSS EASTERN GEORGIA AND THE UPSTATE OF SOUTH CAROLINA
HAVE GENERALLY DISSIPATED THIS MORNING DURING WHAT IS TYPICALLY A
CLIMATOLOGICAL MINIMUM FOR CONVECTION.
THE PRIMARY SHORTWAVE WILL PROGRESS THROUGH THE AREA FROM WEST TO
EAST TODAY. BY EARLY AFTERNOON IT LOOKS AS THOUGH VEERING WINDS ACROSS
SOUTHEAST GA WILL PRODUCE SOME DOWNSLOPE FLOW AND ALLOW FOR
PARTIAL CLEARING WITH TEMPS PUSHING INTO THE UPPER 80S. IN
SOUTHERN SC A DECENT SEABREEZE SHOULD TAKE SHAPE EARLY TO MID
AFTERNOON AND INTERACT WITH THE RESIDUAL SHORTWAVE ENERGY. WITH
DECENT SURFACE BASED CAPES AND COOLING MID-LEVELS THERE SHOULD BE
SCATTERED COVERAGE OF SHOWERS AND TSTMS MAINLY IN SOUTHERN SC THIS
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE COLD FRONT WILL MOVE THROUGH SHORTLY AFTER MIDNIGHT TONIGHT
WITH SLIGHTLY DRIER AIR BEGINNING TO FILTER IN. MOSTLY CLEAR SKIES
EXPECTED WITH TEMPERATURES IN THE LOWER 60S.
FRIDAY AND FRIDAY NIGHT...AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE
MID-ATLANTIC REGION ON FRIDAY. IN WAKE OF THE DEPARTING COLD
FRONT...A DEEP LAYERED NORTHWEST FLOW WILL PREVAIL THROUGH MUCH OF
THE DAY. THE DOWNSLOPE FLOW WILL RESULT IN DRYING ACROSS THE AREA
AND WILL ALSO NEGATE MOST OF THE INITIAL SURGE OF COLD AIR ADVECTION
AS HIGHS SHOULD STILL BE IN THE MID TO UPPER 80S. UNDER MOSTLY SUNNY
SKIES...BREEZY CONDITIONS ARE ALSO EXPECTED. THEN...AS THE UPPER
TROUGH PASSES OFF THE MID-ATLANTIC COAST FRIDAY EVENING...IT WILL
PUSH A SECONDARY COLD FRONT ACROSS THE AREA ALLOWING HIGH PRESSURE
TO BUILD FROM THE GREAT LAKES REGION. THE AIRMASS WILL BEGIN TO
MODIFY SIGNIFICANTLY FOLLOWING THE SECONDARY COLD FRONT WITH
TEMPERATURES PLUMMETING INTO THE UPPER 40S AND LOWER 50S FRIDAY
NIGHT ON A NORTHERLY FLOW.
SATURDAY AND SATURDAY NIGHT...A VERY DRY AIRMASS WILL SETTLE OVER
THE REGION SATURDAY AS HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
GREAT LAKES REGION. PRECIPITABLE WATER VALUES OF .25 TO .40 INCHES
WILL BE ABOUT AS LOW AS THEY CAN GET FOR THIS TIME OF YEAR...OR MORE
THAN 2 STANDARD DEVIATIONS BELOW NORMAL. FORECAST THICKNESS VALUES
ONLY SUPPORT HIGHS IN THE MID TO UPPER 70S...BUT GIVEN FULL SUNSHINE
AND THE HIGHER SUN ANGLE THIS TIME OF YEAR...WILL INDICATE HIGHS IN
THE UPPER 70S TO LOWER 80S ACROSS THE AREA. ANOTHER UNSEASONABLY
COOL NIGHT IS EXPECTED SATURDAY NIGHT...WITH LOWS IN THE LOWER TO
MID 50S.
SUNDAY...A WEAK PRESSURE PATTERN WILL PREVAIL OVER THE REGION. AN
INCREASE IN MID AND HIGH LEVEL MOISTURE WILL SUPPORT SOME CLOUD
COVER BUT THE AIRMASS IS TOO DRY STILL FOR ANY SHOWERS TO DEVELOP.
HIGHS SHOULD BE IN THE LOWER TO MID 80S ACROSS MUCH OF THE AREA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE REGION WILL BE SANDWICHED BETWEEN TWO AREAS OF HIGH PRESSURE
EARLY IN THE WEEK...THE STRONGER OF THE TWO PASSING ACROSS THE
MID-ATLANTIC REGION AND THE OTHER OVER THE NORTHEAST GULF OF MEXICO.
DEEPENING MOISTURE WILL RESULT IN AT LEAST AN INCREASE IN CLOUD
COVER...BUT IT APPEARS THE RAIN-FREE CONDITIONS SHOULD PERSIST
THROUGH MEMORIAL DAY. ATLANTIC HIGH PRESSURE WILL THEN BECOME
ESTABLISHED THROUGH THE MIDDLE OF NEXT WEEK...SUPPORTING MAINLY
DIURNAL ISOLATED CONVECTION EACH AFTERNOON ALONG AND AHEAD OF THE
SEA BREEZE TUESDAY THROUGH THURSDAY. TEMPERATURES WILL MODERATE TO
NEAR NORMAL BY EARLY NEXT WEEK AND CONTINUE NEAR SEASONAL NORMS
THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KCHS AND KSAV
THROUGH 12Z FRIDAY. SCATTERED SHOWERS SHOULD DEVELOP IN ASSOCIATION
WITH A PRE-FRONTAL TROUGH ACROSS SOUTHEAST SC THIS AFTERNOON...WITH
COVERAGE MORE ISOLATED ELSEWHERE. AS A RESULT...VICINITY SHOWERS
ARE INCLUDED IN THE KCHS TAF FROM 16-22Z UNTIL CONFIDENCE IN
TIMING/COVERAGE IMPROVES. HAVE KEPT MENTION OF ANY PRECIPITATION
OUT OF THE KSAV TAF SINCE COVERAGE WILL BE LIMITED ACROSS
SOUTHEAST GA. ANY CEILINGS WILL REMAIN VFR OUTSIDE OF
CONVECTION...WITH CLEARING EXPECTED TONIGHT.
EXTENDED AVIATION...VFR CONDITIONS WILL PREVAIL. GUSTY WINDS ARE
POSSIBLE FRIDAY AFTERNOON.
&&
.MARINE...
WINDS/SEAS WILL BE FAIRLY LOW THROUGH TODAY...THEN WINDS INCREASE
OUT OF THE SW AND W TONIGHT AS A COLD FRONT PUSHES THROUGH THE
WATERS. WIND SPEEDS WILL TOP OUT AROUND 15 KT BUT THE OFFSHORE
FETCH WILL LIMIT THE BUILDING OF SEAS TO NO HIGHER THAN 4 FT.
FRIDAY THROUGH TUESDAY...A NORTHWEST FLOW WILL DEVELOP ON FRIDAY IN
WAKE OF A DEPARTING COLD FRONT. A SECONDARY COLD FRONT WILL THEN
MOVE THROUGH BY FRIDAY EVENING...WITH A STRONGER NORTHERLY SURGE
DEVELOPING IN ITS WAKE FRIDAY NIGHT INTO EARLY SATURDAY...POSSIBLY
RESULTING IN SMALL CRAFT ADVISORY CONDITIONS OVER A PORTION OF THE
WATERS.
CONDITIONS WILL THEN IMPROVE LATER IN THE WEEKEND WITH WINDS/SEAS
EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH
EARLY NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...JRL/JAQ
SHORT TERM...JRL/JAQ
LONG TERM...JAQ
AVIATION...JAQ
MARINE...JRL/JAQ
TIDES/COASTAL FLOODING...
000
FXUS62 KGSP 231144
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
744 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1155 UTC UPDATE...POPS HAVE BEEN INCREASED IN THE NORTHERN NC
MOUNTAINS AND SOUTHEAST OF KCLT PER RADAR TRENDS.
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AT KCLT...MVFR CIG RESTRICTION HAS FINALLY DEVELOPED AND WILL BE
CARRIED INITIALLY. THE LATEST GUIDANCE SUPPORTS VFR...SO THE
RESTRICTION WILL ONLY BE TEMPORARY FOR NOW. SW WINDS WILL APPROACH
10 KNOTS THIS MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE
RESTRICTIONS IS EXPECTED THIS AFTERNOON AS A COLD FRONT MOVES
THROUGH FROM THE W... AND ANOTHER APPROACHES FROM THE NW. CONVECTION
WILL MOVE OFF TO THE EAST BY THIS EVENING....WHILE SW WINDS VEER TO
NW AND BECOME GUSTY. MODEL TIME HEIGHTS SUGGEST THE A LOW VFR CIG
WILL PERSIST INTO THIS EVENING.
ELSEWHERE...RESTRICTIONS WILL END BY MID MORNING AS WINDS COME UP
FROM THE SW IN THE FOOTHILLS AND NW IN THE MOUNTAINS. ADDITIONAL
CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY BETWEEN A
DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING FROM THE
NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE FOOTHILLS AND
BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE EVENING.
OVERNIGHT PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
BORDERING TN THIS EVENING IN NW UPSLOPE FLOW.
OUTLOOK...VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 87% HIGH 98% HIGH 100% HIGH 100%
KGSP HIGH 87% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 94% HIGH 100% HIGH 98% HIGH 83%
KHKY HIGH 83% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 92% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 92% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KCAE 231022
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
622 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE AND INSTABILITY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH
WAS SUPPORTING SCATTERED SHOWERS EARLY THIS MORNING. SATELLITE
TRENDS AND THE MODELS INDICATE DEEPER MOISTURE ASSOCIATED WITH
THE SHORTWAVE TROUGH WILL SHIFT EAST OF THE FORECAST AREA EARLY
THIS AFTERNOON. A PRE-FRONTAL TROUGH WILL BE IN THE FORECAST AREA
THROUGH TODAY. CONVERGENCE ASSOCIATED WITH THIS FEATURE PLUS
DIURNAL HEATING SHOULD SUPPORT THUNDERSTORMS BUT EXPECT LIMITED
COVERAGE BECAUSE OF DIMINISHED MOISTURE BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS AFTERNOON. MAINTAINED CHANCE POPS WITH
THE GREATER VALUES IN THE NORTHEAST PART CLOSER TO THE DEEPER
MOISTURE AND MORE CONVERGENCE ASSOCIATED WITH THE SURFACE TROUGH.
MODERATE INSTABILITY MAY SUPPORT DAMAGING WIND WITH A FEW OF THE
THUNDERSTORMS. WET-BULB ZERO HEIGHTS ALSO SUPPORT HAIL. THE
TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
CONVERGENCE ASSOCIATED WITH THE COLD FRONT MAY SUPPORT
THUNDERSTORMS EARLY. COVERAGE SHOULD STILL BE LIMITED WITH DEEPER
MOISTURE EAST OF THE AREA. DRYING BEHIND THE FRONT SHOULD DOMINATE
LATE TONIGHT THROUGH FRIDAY NIGHT. MIXING ASSOCIATED WITH THE
FRONT SUPPORTED THE WARMER TEMPERATURE GUIDANCE TONIGHT. WE WILL
GET OFF TO A RELATIVELY WARM START SO THE WARMER GUIDANCE APPEARED
BETTER FRIDAY. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FRIDAY NIGHT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. EXPECT SOME INCREASE IN MOISTURE BEGINNING MONDAY. THE
GFS AND ECMWF DISPLAY A WARM FRONT DEVELOPING NEAR THE AREA. THE
GFS IS FARTHER NORTHWARD WITH THE PLACEMENT OF THE FRONT. THE GFS
ALSO SHOWS LESS MOISTURE IN THE FORECAST AREA. BOTH MODELS SHOW
AN INCREASE IN H5 RIDGING WHICH SHOULD LIMIT THUNDERSTORMS.
BELIEVE THE BEST FORECAST FOR NOW IS AN AVERAGE OF THE GFS AND
ECMWF MOS. FORECASTED SLIGHT CHANCE POPS TUESDAY AND WEDNESDAY.
&&
.AVIATION /10Z THURSDAY THROUGH TUESDAY/...
CONVECTION CONTINUES TO DIMINISH AS IT MOVES ENE ACROSS THE AREA.
SHOWERS SHOULD END BY AROUND 12Z-13Z. SOME IFR/MVFR CIGS WILL LINGER
UNTIL AROUND 13Z. UPPER IMPULSE AND SURFACE TROUGH WILL MOVE THROUGH
LATER TODAY...POSSIBLY LEADING TO SCT SHRA/TSRA. DUE TO THE
SCATTERED NATURE OF THE CONVECTION...WILL NOT MENTION PRECIPITATION
AT ANY OF THE TAF SITES FOR THE AFTERNOON HOURS. BY LATE THIS
EVENING...SKIES SHOULD BEGIN TO CLEAR AS DRIER AIR MOVES INTO THE
AREA FROM THE WEST.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 231014
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
614 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1015 UTC UPDATE...VISIBILITY HAS BEEN UPDATED FROM OBSERVATIONS...
RESULTING IN LESS FOG COVERAGE...AND GREATER VISIBILITY VALUES.
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD
SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR
RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND
MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN
THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS
IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE
W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO
THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME
GUSTY.
ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY.
EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE
POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND
TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE
WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS.
ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY
BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING
FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE
FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE
EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
THURSDAY EVENING IN NW UPSLOPE FLOW.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
10-16Z 16-22Z 22-04Z 04-10Z
KCLT HIGH 92% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 90% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 90% HIGH 100% HIGH 100% HIGH 86%
KHKY HIGH 90% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 94% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 92% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KCAE 231007
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
607 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE AND INSTABILITY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH
WAS SUPPORTING SCATTERED SHOWERS EARLY THIS MORNING. SATELLITE
TRENDS AND THE MODELS INDICATE DEEPER MOISTURE ASSOCIATED WITH
THE SHORTWAVE TROUGH WILL SHIFT EAST OF THE FORECAST AREA EARLY
THIS AFTERNOON. A PRE-FRONTAL TROUGH WILL BE IN THE FORECAST AREA
THROUGH TODAY. CONVERGENCE ASSOCIATED WITH THIS FEATURE PLUS
DIURNAL HEATING SHOULD SUPPORT THUNDERSTORMS BUT EXPECT LIMITED
COVERAGE BECAUSE OF DIMINISHED MOISTURE BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS AFTERNOON. MAINTAINED CHANCE POPS WITH
THE GREATER VALUES IN THE NORTHEAST PART CLOSER TO THE DEEPER
MOISTURE AND MORE CONVERGENCE ASSOCIATED WITH THE SURFACE TROUGH.
MODERATE INSTABILITY MAY SUPPORT DAMAGING WIND WITH A FEW OF THE
THUNDERSTORMS. WET-BULB ZERO HEIGHTS ALSO SUPPORT HAIL. THE
TEMPERATURE GUIDANCE WAS CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
CONVERGENCE ASSOCIATED WITH THE COLD FRONT MAY SUPPORT
THUNDERSTORMS EARLY. COVERAGE SHOULD STILL BE LIMITED WITH DEEPER
MOISTURE EAST OF THE AREA. DRYING BEHIND THE FRONT SHOULD DOMINATE
LATE TONIGHT THROUGH FRIDAY NIGHT. MIXING ASSOCIATED WITH THE
FRONT SUPPORTED THE WARMER TEMPERATURE GUIDANCE TONIGHT. WE WILL
GET OFF TO A RELATIVELY WARM START SO THE WARMER GUIDANCE APPEARED
BETTER FRIDAY. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FRIDAY NIGHT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. EXPECT SOME INCREASE IN MOISTURE BEGINNING MONDAY. THE
GFS AND ECMWF DISPLAY A WARM FRONT DEVELOPING NEAR THE AREA. THE
GFS IS FARTHER NORTHWARD WITH THE PLACEMENT OF THE FRONT. THE GFS
ALSO SHOWS LESS MOISTURE IN THE FORECAST AREA. BOTH MODELS SHOW
AN INCREASE IN H5 RIDGING WHICH SHOULD LIMIT THUNDERSTORMS.
BELIEVE THE BEST FORECAST FOR NOW IS AN AVERAGE OF THE GFS AND
ECMWF MOS. FORECASTED SLIGHT CHANCE POPS TUESDAY AND WEDNESDAY.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO SLOWLY WEAKEN AS IT MOVES TO THE ENE. MOST
ACTIVITY CURRENTLY CONFINED TO THE UPSTATE SC AND EASTERN GA. HIGH
RES MODELS CONTINUE TO SUGGEST THE ACTIVITY WILL GRADUALLY WEAKEN AS
IT MOVES INTO THE AREA. WILL MENTION A TEMPO GROUP FOR SHOWERS FOR
AGS/DNL UNTIL AROUND 09Z-10Z...AND 10Z-11Z AT CAE/CUB. NOT ENOUGH
CONFIDENCE TO MENTION PRECIP AT OGB AT THIS TIME.
GUIDANCE ALSO CONTINUING TO INDICATE CIG RESTRICTIONS EARLY THIS
MORNING...IN A CONTINUED MOIST SOUTHERLY LOW LEVEL FLOW. FOR
NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL MONITOR LATEST
GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED. UPPER IMPULSE AND
SURFACE TROUGH WILL MOVE THROUGH LATER TODAY...POSSIBLY LEADING TO
SCT SHRA/TSRA. DUE TO THE SCATTERED NATURE OF THE CONVECTION...WILL
NOT MENTION PRECIPITATION AT ANY OF THE TAF SITES FOR THE AFTERNOON
HOURS. BY LATE THIS EVENING...SKIES SHOULD BEGIN TO CLEAR AS DRIER
AIR MOVES INTO THE AREA FROM THE WEST.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 230938
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
538 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
0930 UTC UPDATE...POPS HAVE BEEN ADJUSTED PER RADAR TRENDS...WITH
GREATER COVERAGE IN THE SC PIEDMONT.
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD
SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR
RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND
MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN
THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS
IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE
W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO
THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME
GUSTY.
ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY.
EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE
POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND
TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE
WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS.
ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY
BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING
FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE
FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE
EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
THURSDAY EVENING IN NW UPSLOPE FLOW.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-09Z
KCLT HIGH 94% HIGH 98% HIGH 100% HIGH 100%
KGSP HIGH 86% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 84% HIGH 100% HIGH 100% HIGH 90%
KHKY HIGH 87% HIGH 100% HIGH 100% HIGH 100%
KGMU MED 79% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 90% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KCAE 230832
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
431 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE AND INSTABILITY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH
WAS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS EARLY THIS
MORNING. SATELLITE TRENDS AND THE MODELS INDICATE DEEPER MOISTURE
ASSOCIATED WITH THIS FEATURE WILL SHIFT EAST OF THE FORECAST AREA
LATER THIS MORNING. A PRE-FRONTAL TROUGH WILL BE IN THE FORECAST
AREA TODAY. CONVERGENCE ASSOCIATED WITH THIS FEATURE PLUS DIURNAL
HEATING SHOULD SUPPORT THUNDERSTORMS BUT EXPECT LIMITED COVERAGE
BECAUSE OF DIMINISHED MOISTURE BEHIND THE MID-LEVEL SHORTWAVE
TROUGH. MAINTAINED CHANCE POPS WITH THE GREATER VALUES IN THE
NORTHEAST PART CLOSER TO DEEPER MOISTURE AND MORE CONVERGENCE
ASSOCIATED WITH THE SURFACE TROUGH. MODERATE INSTABILITY MAY
SUPPORT DAMAGING WIND WITH A FEW OF THE THUNDERSTORMS. WET-BULB
ZERO HEIGHTS ALSO SUPPORT HAIL. THE TEMPERATURE GUIDANCE WAS
CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
CONVERGENCE ASSOCIATED WITH THE COLD FRONT MAY SUPPORT
THUNDERSTORMS EARLY. COVERAGE SHOULD STILL BE LIMITED WITH DEEPER
MOISTURE EAST OF THE AREA. DRYING BEHIND THE FRONT SHOULD DOMINATE
LATE TONIGHT THROUGH FRIDAY NIGHT. MIXING ASSOCIATED WITH THE
FRONT SUPPORTED THE WARMER TEMPERATURE GUIDANCE TONIGHT. WE WILL
GET OFF TO A RELATIVELY WARM START SO THE WARMER GUIDANCE APPEARED
BETTER FRIDAY. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FRIDAY NIGHT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. EXPECT SOME INCREASE IN MOISTURE BEGINNING MONDAY. THE
GFS AND ECMWF DISPLAY A WARM FRONT DEVELOPING NEAR THE AREA. THE
GFS IS FARTHER NORTHWARD WITH THE PLACEMENT OF THE FRONT. THE GFS
ALSO SHOWS LESS MOISTURE IN THE FORECAST AREA. BOTH MODELS SHOW
AN INCREASE IN H5 RIDGING WHICH SHOULD LIMIT THUNDERSTORMS.
BELIEVE THE BEST FORECAST FOR NOW IS AN AVERAGE OF THE GFS AND
ECMWF MOS. FORECASTED SLIGHT CHANCE POPS TUESDAY AND WEDNESDAY.
&&
.AVIATION /08Z THURSDAY THROUGH TUESDAY/...
CONVECTION CONTINUES TO SLOWLY WEAKEN AS IT MOVES TO THE ENE. MOST
ACTIVITY CURRENTLY CONFINED TO THE UPSTATE SC AND EASTERN GA. HIGH
RES MODELS CONTINUE TO SUGGEST THE ACTIVITY WILL GRADUALLY WEAKEN AS
IT MOVES INTO THE AREA. WILL MENTION A TEMPO GROUP FOR SHOWERS FOR
AGS/DNL UNTIL AROUND 09Z-10Z...AND 10Z-11Z AT CAE/CUB. NOT ENOUGH
CONFIDENCE TO MENTION PRECIP AT OGB AT THIS TIME.
GUIDANCE ALSO CONTINUING TO INDICATE CIG RESTRICTIONS EARLY THIS
MORNING...IN A CONTINUED MOIST SOUTHERLY LOW LEVEL FLOW. FOR
NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL MONITOR LATEST
GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED. UPPER IMPULSE AND
SURFACE TROUGH WILL MOVE THROUGH LATER TODAY...POSSIBLY LEADING TO
SCT SHRA/TSRA. DUE TO THE SCATTERED NATURE OF THE CONVECTION...WILL
NOT MENTION PRECIPITATION AT ANY OF THE TAF SITES FOR THE AFTERNOON
HOURS. BY LATE THIS EVENING...SKIES SHOULD BEGIN TO CLEAR AS DRIER
AIR MOVES INTO THE AREA FROM THE WEST.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 230820
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
420 AM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH LATE TONIGHT WITH DRY HIGH PRESSURE
BUILDING IN THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A PRONOUNCED SHORTWAVE DISTURBANCE TREKKING ACROSS EASTERN GA
EARLY THIS MORNING CONTINUES TO DRIVE A WEAKENING BAND OF RAIN
SHOWERS INTO OUR FAR WESTERN ZONES. AS WE MOVE CLOSER TO THE
CLIMATOLOGICAL MINIMUM FOR CONVECTION...THIS ACTIVITY LOOKS LIKE
IT WILL DISSIPATE BEFORE MAKING ITS WAY INTO SOUTHERN SC. WE HAVE
SOME POPS ACROSS SOUTHEAST GA THROUGH DAYBREAK BUT WITH A
DIMINISHING TREND. THE INCREASE IN MID-LEVEL CLOUDINESS IN
CONVECTIVE DEBRIS WILL AT LEAST HELP LIMIT FOG POTENTIAL OVER THE
AREA THIS MORNING.
AFTER DAYBREAK THE PRIMARY VORT WILL PROGRESS THROUGH THE AREA
FROM WEST TO EAST. BY EARLY AFTERNOON IT LOOKS AS THOUGH VEERING
WINDS ACROSS SOUTHEAST GA WILL PRODUCE SOME DOWNSLOPE FLOW AND
ALLOW FOR PARTIAL CLEARING WITH TEMPS PUSHING INTO THE UPPER 80S.
IN SOUTHERN SC A DECENT SEABREEZE SHOULD TAKE SHAPE EARLY TO MID
AFTERNOON AND INTERACT WITH THE RESIDUAL SHORTWAVE ENERGY. WITH
DECENT SURFACE BASED CAPES AND COOLING MID-LEVELS THERE SHOULD BE
SCATTERED COVERAGE OF SHOWERS AND TSTMS MAINLY IN SOUTHERN SC THIS
AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE COLD FRONT WILL MOVE THROUGH SHORTLY AFTER MIDNIGHT TONIGHT
WITH SLIGHTLY DRIER AIR BEGINNING TO FILTER IN. MOSTLY CLEAR SKIES
EXPECTED WITH TEMPERATURES IN THE LOWER 60S.
FRIDAY AND FRIDAY NIGHT...AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE
MID-ATLANTIC REGION ON FRIDAY. IN WAKE OF THE DEPARTING COLD
FRONT...A DEEP LAYERED NORTHWEST FLOW WILL PREVAIL THROUGH MUCH OF
THE DAY. THE DOWNSLOPE FLOW WILL RESULT IN DRYING ACROSS THE AREA
AND WILL ALSO NEGATE MOST OF THE INITIAL SURGE OF COLD AIR ADVECTION
AS HIGHS SHOULD STILL BE IN THE MID TO UPPER 80S. UNDER MOSTLY SUNNY
SKIES...BREEZY CONDITIONS ARE ALSO EXPECTED. THEN...AS THE UPPER
TROUGH PASSES OFF THE MID-ATLANTIC COAST FRIDAY EVENING...IT WILL
PUSH A SECONDARY COLD FRONT ACROSS THE AREA ALLOWING HIGH PRESSURE
TO BUILD FROM THE GREAT LAKES REGION. THE AIRMASS WILL BEGIN TO
MODIFY SIGNIFICANTLY FOLLOWING THE SECONDARY COLD FRONT WITH
TEMPERATURES PLUMMETING INTO THE UPPER 40S AND LOWER 50S FRIDAY
NIGHT ON A NORTHERLY FLOW.
SATURDAY AND SATURDAY NIGHT...A VERY DRY AIRMASS WILL SETTLE OVER
THE REGION SATURDAY AS HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
GREAT LAKES REGION. PRECIPITABLE WATER VALUES OF .25 TO .40 INCHES
WILL BE ABOUT AS LOW AS THEY CAN GET FOR THIS TIME OF YEAR...OR MORE
THAN 2 STANDARD DEVIATIONS BELOW NORMAL. FORECAST THICKNESS VALUES
ONLY SUPPORT HIGHS IN THE MID TO UPPER 70S...BUT GIVEN FULL SUNSHINE
AND THE HIGHER SUN ANGLE THIS TIME OF YEAR...WILL INDICATE HIGHS IN
THE UPPER 70S TO LOWER 80S ACROSS THE AREA. ANOTHER UNSEASONABLY
COOL NIGHT IS EXPECTED SATURDAY NIGHT...WITH LOWS IN THE LOWER TO
MID 50S.
SUNDAY...A WEAK PRESSURE PATTERN WILL PREVAIL OVER THE REGION. AN
INCREASE IN MID AND HIGH LEVEL MOISTURE WILL SUPPORT SOME CLOUD
COVER BUT THE AIRMASS IS TOO DRY STILL FOR ANY SHOWERS TO DEVELOP.
HIGHS SHOULD BE IN THE LOWER TO MID 80S ACROSS MUCH OF THE AREA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE REGION WILL BE SANDWICHED BETWEEN TWO AREAS OF HIGH PRESSURE
EARLY IN THE WEEK...THE STRONGER OF THE TWO PASSING ACROSS THE
MID-ATLANTIC REGION AND THE OTHER OVER THE NORTHEAST GULF OF MEXICO.
DEEPENING MOISTURE WILL RESULT IN AT LEAST AN INCREASE IN CLOUD
COVER...BUT IT APPEARS THE RAIN-FREE CONDITIONS SHOULD PERSIST
THROUGH MEMORIAL DAY. ATLANTIC HIGH PRESSURE WILL THEN BECOME
ESTABLISHED THROUGH THE MIDDLE OF NEXT WEEK...SUPPORTING MAINLY
DIURNAL ISOLATED CONVECTION EACH AFTERNOON ALONG AND AHEAD OF THE
SEA BREEZE TUESDAY THROUGH THURSDAY. TEMPERATURES WILL MODERATE TO
NEAR NORMAL BY EARLY NEXT WEEK AND CONTINUE NEAR SEASONAL NORMS
THROUGH THE END OF THE FORECAST PERIOD.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
ASSUMING NONE OF THE UPSTREAM SHOWER AND TSTM ACTIVITY MAKES IT
INTO THE TERMINALS PRIOR TO DAYBREAK...FAIRLY QUIET CONDITIONS
ANTICIPATED. WE EXPECT AN INCREASE IN MID AND HIGH CLOUDS LATE
TONIGHT IN ASSOCIATION WITH A SHORTWAVE MOVING THROUGH. THIS WILL
LIMIT FOG POTENTIAL. LATER TODAY...A PRE-FRONTAL TROUGH WILL PUSH
THROUGH MAINLY SOUTHERN SC. CONVERGENCE ALONG THIS BOUNDARY MAY
SPUR SOME SHOWERS OR STORMS NEAR KCHS EARLY THIS AFTERNOON.
OTHERWISE DRYING CONDITIONS BY EARLY THIS EVENING WITH SKIES
GRADUALLY CLEARING.
EXTENDED AVIATION...VFR CONDITIONS WILL PREVAIL. GUSTY WINDS ARE
POSSIBLE FRIDAY AFTERNOON.
&&
.MARINE...
WINDS/SEAS WILL BE FAIRLY LOW THROUGH TODAY...THEN WINDS INCREASE
OUT OF THE SW AND W TONIGHT AS A COLD FRONT PUSHES THROUGH THE
WATERS. WIND SPEEDS WILL TOP OUT AROUND 15 KT BUT THE OFFSHORE
FETCH WILL LIMIT THE BUILDING OF SEAS TO NO HIGHER THAN 4 FT.
FRIDAY THROUGH TUESDAY...A NORTHWEST FLOW WILL DEVELOP ON FRIDAY IN
WAKE OF A DEPARTING COLD FRONT. A SECONDARY COLD FRONT WILL THEN
MOVE THROUGH BY FRIDAY EVENING...WITH A STRONGER NORTHERLY SURGE
DEVELOPING IN ITS WAKE FRIDAY NIGHT INTO EARLY SATURDAY...POSSIBLY
RESULTING IN SMALL CRAFT ADVISORY CONDITIONS OVER A PORTION OF THE
WATERS.
CONDITIONS WILL THEN IMPROVE LATER IN THE WEEKEND WITH WINDS/SEAS
EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH
EARLY NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...JRL
SHORT TERM...JAQ/JRL
LONG TERM...JAQ
AVIATION...JAQ/JRL
MARINE...JAQ/JRL
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 230807
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
407 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MOISTURE AND INSTABILITY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH
WAS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS EARLY THIS
MORNING. SATELLITE TRENDS AND THE MODELS INDICATE DEEPER MOISTURE
ASSOCIATED WITH THIS FEATURE WILL SHIFT EAST OF THE FORECAST AREA
LATER THIS MORNING. A PRE-FRONTAL TROUGH WILL BE IN THE FORECAST
AREA TODAY. CONVERGENCE ASSOCIATED WITH THIS FEATURE PLUS DIURNAL
HEATING SHOULD SUPPORT THUNDERSTORMS BUT EXPECT LIMITED COVERAGE
BECAUSE OF DIMINISHED MOISTURE BEHIND THE MID-LEVEL SHORTWAVE
TROUGH. MAINTAINED CHANCE POPS WITH THE GREATER VALUES IN THE
NORTHEAST PART CLOSER TO DEEPER MOISTURE AND MORE CONVERGENCE
ASSOCIATED WITH THE SURFACE TROUGH. MODERATE INSTABILITY MAY
SUPPORT DAMAGING WIND WITH A FEW OF THE THUNDERSTORMS. WET-BULB
ZERO HEIGHTS ALSO SUPPORT HAIL. THE TEMPERATURE GUIDANCE WAS
CLOSE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
CONVERGENCE ASSOCIATED WITH THE COLD FRONT MAY SUPPORT
THUNDERSTORMS EARLY. COVERAGE SHOULD STILL BE LIMITED WITH DEEPER
MOISTURE EAST OF THE AREA. DRYING BEHIND THE FRONT SHOULD DOMINATE
LATE TONIGHT THROUGH FRIDAY NIGHT. MIXING ASSOCIATED WITH THE
FRONT SUPPORTED THE WARMER TEMPERATURE GUIDANCE TONIGHT. WE WILL
GET OFF TO A RELATIVELY WARM START SO THE WARMER GUIDANCE APPEARED
BETTER FRIDAY. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FRIDAY NIGHT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. EXPECT SOME INCREASE IN MOISTURE BEGINNING MONDAY. THE
GFS AND ECMWF DISPLAY A WARM FRONT DEVELOPING NEAR THE AREA. THE
GFS IS FARTHER NORTHWARD WITH THE PLACEMENT OF THE FRONT. THE GFS
ALSO SHOWS LESS MOISTURE IN THE FORECAST AREA. BOTH MODELS SHOW
AN INCREASE IN H5 RIDGING WHICH SHOULD LIMIT THUNDERSTORMS.
BELIEVE THE BEST FORECAST FOR NOW IS AN AVERAGE OF THE GFS AND
ECMWF MOS. FORECASTED SLIGHT CHANCE POPS TUESDAY AND WEDNESDAY.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO SLOWLY WEAKEN AS IT MOVES TO THE ENE. MOST
ACTIVITY CURRENTLY CONFINED TO THE UPSTATE SC AND EASTERN GA. HIGH
RES MODELS CONTINUE TO SUGGEST THE ACTIVITY WILL GRADUALLY WEAKEN AS
IT MOVES INTO THE AREA. WILL MENTION A TEMPO GROUP FOR SHOWERS FOR
AGS/DNL UNTIL AROUND 09Z-10Z...OTHERWISE NOT ENOUGH CONFIDENCE TO
MENTION PRECIP AT THE OTHER TAF SITES.
GUIDANCE ALSO CONTINUING TO INDICATE CIG RESTRICTIONS EARLY THIS
MORNING...IN A CONTINUED MOIST SOUTHERLY LOW LEVEL FLOW. FOR
NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL MONITOR LATEST
GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED. UPPER IMPULSE AND
SURFACE TROUGH WILL MOVE THROUGH LATER TODAY...POSSIBLY LEADING TO
SCT SHRA/TSRA. DUE TO THE SCATTERED NATURE OF THE CONVECTION...WILL
NOT MENTION PRECIPITATION AT ANY OF THE TAF SITES FOR THE AFTERNOON
HOURS. BY LATE THIS EVENING...SKIES SHOULD BEGIN TO CLEAR AS DRIER
AIR MOVES INTO THE AREA FROM THE WEST.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 230751
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
351 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION TODAY. A COLD FRONT MOVES THROUGH THE AREA TONIGHT...BEFORE A
COOLER AND DRIER AIRMASS SETTLES IN FOR THE WEEKEND. THE AIRMASS
MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 300 AM EST THURSDAY...AN UPPER TROUGH AXIS WILL CROSS THE OH AND
TN VALLEYS TODAY...CROSS THE SOUTHERN APPALACHIANS THIS EVENING...
THEN MOVES SLOWLY OVER THE EASTERN SEABOARD TONIGHT. THE REMAINS OF
A COLD FRONT WILL CONTINUE TO CROSS OUR AREA EARLY TODAY..EXITING
THE AREA TO THE EAST THIS AFTERNOON. A STRONG COLD FRONT WILL
APPROACH FROM THE NW TODAY...REACHING THE MOUNTAINS BY THIS
EVENING...AND CROSSING THE ENTIRE AREA SHORTLY AFTER MIDNIGHT.
THE ATMOSPHERE WILL DESTABILIZE AGAIN TODAY...WITH MODEST WIND
SHEAR...AND SUFFICIENT DRY AIR ALOFT FOR DOWNDRAFT PRODUCTION. MODEL
TIME HEIGHTS SHOW THE BEST LIFT BETWEEN 18 AND 21Z. A VEERING LOW
LEVEL FLOW WILL DRY OUT THE LOWER LEVELS BEFORE LIFT IS MAXIMIZED IN
THE FOOTHILLS...BUT DEEPER MOISTURE WILL REMAIN IN THE PIEDMONT...
WHERE HEAVIER RAINFALL CAN BE EXPECTED. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL TODAY.
AS THE COLD FRONT CROSSES THE ARE THIS EVENING...WINDS WILL VEER NW.
MODEL TIME HEIGHTS SHOW SOME LOW LEVEL MOISTURE PERSISTING EAST OF
THE BLUE RIDGE...DESPITE A DOWNSLOPE FLOW...AND LIGHT RAINFALL MAY
PERSIST INTO THE EVENING. POST FRONTAL PRECIPITATION WILL BE BEST
AND MOST PROLONGED ALONG THE TN BORDER WITH NC...WHERE A PRONOUNCED
MOIST NW UPSLOPE FLOW WILL SET UP AND LINGER OVERNIGHT. MINIMUM
TEMPERATURES WILL BE NEAR NORMAL.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 210 AM THURSDAY...AXIS OF AN UPPER TROF SWINGS ACROSS THE AREA
FRI. AT THE SFC...PRESSURE GRADIENT TIGHTENS ACROSS THE AREA AS A
COLD FRONT SLOWLY MOVES EAST AND HIGH PRESSURE SLOWLY MOVES IN FROM
THE WEST. LOW LEVEL MOISTURE LINGERS OVER THE MTNS DURING THE
MORNING...KEEPING SOME SCT RAIN SHOWERS THERE IN THE NWLY UPSLOPE
FLOW. THE SHRA DISSIPATE BY AFTERNOON AS THE MOISTURE DIMINISHES.
THE WIND AND COOLER AIR MASS WILL BE THE BIGGER STORIES. MODERATELY
STRONG LOW LEVEL WINDS MOVE IN AND MIXING SHUD BE ABLE TO TAP THOSE
WINDS DURING THE DAY. ALTHOUGH A WINDY DAY IS EXPECTED...GUSTS SHUD
REMAIN BELOW WIND ADV LEVELS. WITH THE COOLER AIR MASS MOVING IN...
HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE ARE FRI NITE AS NWLY
FLOW DEVELOPS ALOFT. THE GUSTY WINDS SHUD COME TO AN END DURING THE
EVENING. HOWEVER...THE COLD AIR MASS WILL DROP LOWS TO AROUND 15
DEGREES BELOW NORMAL. IN FACT...TEMPS IN THE NC MTN VALLEYS WILL BE
COLD ENUF FOR FROST. IF THE WIND CAN DIMINISH ENUF...WHICH LOOKS
QUITE POSSIBLE FOR THE SWRN VALLEYS...THEN A FROST ADV WOULD BE
NEEDED.
NWLY FLOW ALOFT REMAINS OVER THE AREA SAT AND SAT NITE AS A FEW WEAK
SHORT WAVES MOVE THRU. AT THE SFC...A WEAK BACK DOOR COLD FRONT
DROPS INTO THE AREA LATE SAT OR SAT NITE. ALTHOUGH MOISTURE
INCREASES SIGNIFICANTLY AND THERE IS SOME FORCING...THE FCST REMAINS
DRY. HIGHS REMAIN NEARLY STEADY OUTSIDE OF THE MTNS...BUT REBOUND A
FEW DEGREES OVER THE MTNS SAT. LOWS SAT NITE ALSO INCREASE...BUT
REMAIN ABOUT 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 345 AM THURSDAY...THE GFS AND ECMWF ARE IN GENERAL AGREEMENT
ON THE OVERALL PATTERN DURING THE MEDIUM RANGE. HOWEVER...THERE ARE
SOME SIGNIFICANT DETAIL DIFFERENCES...ESPECIALLY AT THE SFC. NWLY
FLOW ALOFT STARTS OUT OVER THE AREA BETWEEN AN UPPER LOW OVER NEW
ENGLAND AND A RIDGE OVER THE CENTRAL CONUS. THIS FLOW CONTINUES THRU
MON ON THE GFS UNTIL THE RIDGE MOVES EAST OVER THE AREA ON TUE WITH
THE RIDGE REMAINING IN PLACE THRU WED. ON THE ECMWF...THE RIDGE DOES
NOT MOVE IN UNTIL WED.
AT THE SFC...A BACK DOOR COLD FRONT STARTS OUT OVER THE AREA. THE
ECMWF TAKES THE FRONT SOUTH OF THE AREA SUN...KEEPS IT THERE MON
THEN MOVES IT BACK NORTH INTO THE AREA TUE AND KEEPS IT STATIONARY
WED. THE GFS KEEPS THE FRONT OVER OR JUST NORTH OF THE AREA SUN AND
MON...THEN SLIDES IT NORTHWARD TUE AND EASTWARD WED. THE GFS WOULD
INDICATE MORE OF A DIURNAL CHC OF CONVECTION EACH DAY...WHILE THE
ECMWF SUGGESTS MORE OF A STEADY CHC OF CONVECTION. THE GFS HAS BEEN
PRETTY CONSISTENT WITH ITS FORECAST FROM RUN TO RUN...WHILE THE
ECMWF HAS NOT. THEREFORE...SINCE NATIONAL GUIDANCE IS CLOSER TO THE
GFS...HAVE FOLLOWED THOSE TRENDS AS WELL. HIGHS A LITTLE BELOW NORMAL
SUN RISE TO AROUND 5 DEGREES ABOVE NORMAL BY WED. LOWS A FEW DEGREES
BELOW NORMAL AT THE BEGINNING OF THE PERIOD RISE TO A FEW DEGREES
ABOVE NORMAL BY THE END.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD
SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR
RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND
MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN
THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS
IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE
W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO
THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME
GUSTY.
ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY.
EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE
POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND
TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE
WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS.
ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY
BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING
FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE
FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE
EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
THURSDAY EVENING IN NW UPSLOPE FLOW.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 86% HIGH 94% HIGH 100% HIGH 100%
KGSP MED 78% HIGH 98% HIGH 100% HIGH 100%
KAVL MED 79% HIGH 94% HIGH 100% HIGH 92%
KHKY MED 71% HIGH 92% HIGH 100% HIGH 100%
KGMU MED 67% HIGH 97% HIGH 100% HIGH 100%
KAND MED 76% HIGH 97% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...JAT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT
000
FXUS62 KCHS 230612
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
212 AM EDT THU MAY 23 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THERE ARE SOME CHANGES THAT WILL TAKE PLACE IN THE LARGER
SCALE...AS THE FIRST SHORT WAVE OFF THE EASTERN FLORIDA COAST WILL
GET LIFTED NE AS THE NEXT LONG WAVE TROUGH IN THE MISSISSIPPI VALLEY
SHIFTS EAST. IN ADVANCE OF THE LONG WAVE IS A DECENT SHORT WAVE
MOVING THROUGH NE AND CENTRAL GA THAT WILL APPROACH OUR BORDER LATE.
AS THIS TRANSPIRES...IT FORCES THE LAST GRIPS OF THE ATLANTIC RIDGE
TO PULL OFFSHORE AFTER MIDNIGHT...AS A PRE-FRONTAL TROUGH IN WESTERN
GEORGIA APPROACHES LATE. THE FORECAST AREA WILL THEN LIE SANDWICHED
BETWEEN THE FIRST SHORT WAVE IN THE NEARBY ATLANTIC AND THE SECOND
IMPULSE AND ITS REFLECTION AT THAT SURFACE. WHILE THERE IS SOME
INCREASE IN LOW LEVEL CONVERGENCE TO THE EAST...THE SYNOPTIC FLOW
MAY VEER TOO FAR TO THE SW TO ALLOW FOR ANYTHING MORE THAN LOW END
POPS OVER CHARLESTON COUNTY CLOSE TO DAYBREAK. UPSTREAM IT APPEARS
THAT THE BEST FORCING WILL STAY TO THE WEST...BUT A FEW SHOWERS OR
T-STORMS COULD SNEAK INTO THE SW CORNER LATE. FOR NOW WE HAVE SHOWN
POPS AT 14 PERCENT OR LESS FOR ALL BUT NORTHERN CHARLESTON COUNTY
AND CANDLER AND JENKINS WHERE 20 POPS WILL BE SUFFICIENT.
WHILE CONDITIONS ARE NOT AS FAVORABLE FOR FOG DEVELOPMENT AS LAST
NIGHT /IE. TOO MUCH WIND IN THE BOUNDARY LAYER UNTIL LATE AND
MUCH LESS RAINFALL/...WE HAVE MAINTAINED MENTION OF PATCHY FOG TO
OUR NW TIER WHERE THEY HAVE A BETTER CHANCE OF ACHIEVING THEIR
CROSS-OVER TEMPS AND FOG STABILITY INDICES ARE IN THE LOWER 20S.
THE MIXING IN THE BOUNDARY LAYER AND AN INCREASE IN CLOUD COVER
WILL LIMIT TEMPS TO ONLY THE MID AND UPPER 60S INLAND FROM THE
SLIGHTLY WARMER BEACHES.
FOR THOSE THAT ARE INTERESTED...TEMPS AGAIN FAILED TO HIT 90
DEGREES AT BOTH KCHS AND KSAV WEDNESDAY. THIS CONTINUES THE
STRETCH OF SUB-90 DEGREE DAYS AT 257 STRAIGHT AT KCHS AND 256
STRAIGHT AT KSAV DATING BACK TO EARLY SEPTEMBER 2012.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
ASSUMING NONE OF THE UPSTREAM SHOWER AND TSTM ACTIVITY MAKES IT
INTO THE TERMINALS PRIOR TO DAYBREAK...FAIRLY QUIET CONDITIONS
ANTICIPATED. WE EXPECT AN INCREASE IN MID AND HIGH CLOUDS LATE
TONIGHT IN ASSOCIATION WITH A SHORTWAVE MOVING THROUGH. THIS WILL
LIMIT FOG POTENTIAL. LATER TODAY...A PRE-FRONTAL TROUGH WILL PUSH
THROUGH MAINLY SOUTHERN SC. CONVERGENCE ALONG THIS BOUNDARY MAY
SPUR SOME SHOWERS OR STORMS NEAR KCHS EARLY THIS AFTERNOON.
OTHERWISE DRYING CONDITIONS BY EARLY THIS EVENING WITH SKIES
GRADUALLY CLEARING.
EXTENDED AVIATION...VFR. WINDS COULD GET A BIT GUSTY FRIDAY AFTERNOON
BEHIND THE SECONDARY FRONT.
&&
.MARINE...
TONIGHT...THE SUB TROPICAL RIDGE IN THE ATLANTIC CENTERED OUT NEAR
32N AND 60W WILL START TO RELAX ITS GRIP ACROSS THE COASTAL WATERS
LATE...AS IT STARTS TO GIVE WAY TO AN UPSTREAM PRE-FRONTAL TROUGH.
THE PRESSURE GRADIENT WILL TEMPORARILY TIGHTEN A BIT BETWEEN THESE
TWO FEATURES...ALLOWING FOR SE AND SOUTH WINDS UP TO 15 KT THROUGH
ABOUT 06-08Z...BEFORE VEERING ABOUT 10-30 DEGREES AND DROPPING
OFF TO 10 OR LESS LATE. SEAS WON/T CHANGE MUCH...AVERAGING 2-4 FT
AND HIGHEST ACROSS THE OUTER GA WATERS. WE/LL NEED TO MONITOR FOR
SOME GUSTY SHOWERS/T-STORMS OVERNIGHT AS LOW LEVEL CONVERGENCE
INCREASES.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...JRL
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...JRL
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 230531
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
131 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE DURING
THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
MOISTURE AND INSTABILITY AHEAD OF A MID-LEVEL SHORTWAVE TROUGH
WAS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS EARLY THIS
MORNING. SATELLITE TRENDS AND THE MODELS INDICATE DEEPER MOISTURE
ASSOCIATED WITH THIS FEATURE WILL SHIFT EAST OF THE FORECAST AREA
LATER THIS MORNING. A PRE-FRONTAL TROUGH WILL BE IN THE FORECAST
AREA TODAY. CONVERGENCE ASSOCIATED WITH THIS FEATURE PLUS DIURNAL
HEATING SHOULD SUPPORT THUNDERSTORMS BUT EXPECT LIMITED COVERAGE
BECAUSE OF DIMINISHED MOISTURE BEHIND THE MID-LEVEL SHORTWAVE
TROUGH. MAINTAINED CHANCE POPS WITH THE GREATER VALUES IN THE
NORTHEAST PART CLOSER TO DEEPER MOISTURE AND MORE CONVERGENCE
ASSOCIATED WITH THE SURFACE TROUGH. MODERATE INSTABILITY MAY
SUPPORT DAMAGING WIND WITH A FEW OF THE THUNDERSTORMS. WET-BULB
ZERO HEIGHTS ALSO SUPPORT HAIL. THE TEMPERATURE GUIDANCE WAS
CLOSE.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
CONVERGENCE ASSOCIATED WITH THE COLD FRONT MAY SUPPORT
THUNDERSTORMS EARLY. COVERAGE SHOULD STILL BE LIMITED WITH DEEPER
MOISTURE EAST OF THE AREA. DRYING BEHIND THE FRONT SHOULD DOMINATE
LATE TONIGHT THROUGH FRIDAY NIGHT. MIXING ASSOCIATED WITH THE
FRONT SUPPORTED THE WARMER TEMPERATURE GUIDANCE TONIGHT. WE WILL
GET OFF TO A RELATIVELY WARM START SO THE WARMER GUIDANCE APPEARED
BETTER FRIDAY. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FRIDAY NIGHT.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA. THE
GFS ENSEMBLE MEAN PLUS GFS AND ECMWF MOS SUPPORTED VERY LOW POPS. EXPECT
BELOW NORMAL TEMPERATURES DURING THE WEEKEND...AND NEAR NORMAL
READINGS DURING THE REST OF THE MEDIUM-RANGE PERIOD.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
CONVECTION CONTINUES TO SLOWLY WEAKEN AS IT MOVES TO THE ENE. MOST
ACTIVITY CURRENTLY CONFINED TO THE UPSTATE SC...STRETCHING SW ACROSS
NE AND CENT GA. LATEST HIGH RES MODELS SUGGEST THE ACTIVITY WILL
GRADUALLY WEAKEN AND DISSIPATE AS IT APPROACHES THE CSRA. WILL
MENTION A TEMPO GROUP FOR SHOWERS FOR AGS/DNL UNTIL AROUND
09Z...OTHERWISE NOT ENOUGH CONFIDENCE TO MENTION PRECIP AT THE OTHER
TAF SITES.
GUIDANCE ALSO CONTINUING TO INDICATE CIG RESTRICTIONS LATE
TONIGHT/EARLY THURSDAY MORNING...IN A CONTINUED MOIST SOUTHERLY LOW
LEVEL FLOW. FOR NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL
MONITOR LATEST GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED.
UPPER IMPULSE AND SURFACE TROUGH WILL MOVE THROUGH
THURSDAY...POSSIBLY LEADING TO SCT SHRA/TSRA. CURRENT THINKING IS
THAT MOST OF THE ACTIVITY THURSDAY WILL BE EAST OF THE TERMINALS.
WILL NOT MENTION IN THE TAFS AT THIS TIME. BY LATE THIS
EVENING...SKIES SHOULD BEGIN TO CLEAR AS DRIER AIR MOVES INTO THE
AREA FROM THE WEST.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 230521
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
121 AM EDT THU MAY 23 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
0500 UTC UPDATE...POPS WERE REALIGNED TO CONCUR WITH RADAR
TRENDS...MOVING A LINE OF CONVECTION ACROSS INTERSTATE 77 OVER THE
NET FEW HOURS...ANOTHER CLUSTER OF STORMS ACROSS THE UPPER SAVANNAH
RIVER VALLEY...AND A THIRD GROUP OF STORMS FROM THE GA MOUNTAINS
INTO SC. WINDS WERE UPDATED WITH A BLEND OF THE LATEST ADJMAV AND
NAM...FAVORING THE LATER FOR HIGHER WINDS IN THE MOUNTAINS.
VISIBILITY WAS UPDATED FORM OBSERVATIONS AND A BLEND OF THE ADJMAV
AND ADJMET...LOWERED SLIGHTLY TOWARD THE LAMP GUIDANCE.
AS OF 1045 PM...BROKEN MULTICELL LINE OF THUNDERSTORMS CONTINUES TO
MOVE TO THE EAST NORTHEAST ACROSS THE UPSTATE IN ASSOCIATION WITH
CONVERGENCE NEAR FRONTAL BOUNDARY. ELSEWHERE...DISCRETE PULSE
SHOWERS AND THUNDERSTORMS WERE PRESENT ACROSS PORTIONS OF THE NORTH
CAROLINA FOOTHILLS/PIEDMONT. THE MAIN THREATS WITH ANY OF THESE
THUNDERSTORMS ARE BRIEF HEAVY RAINFALL...LARGE HAIL...DAMAGING
WINDS...AND FREQUENT CLOUD TO GROUND LIGHTNING. AS FOR THE
FCST...THE ACTIVITY CURRENTLY EXTENDING ACROSS THE WESTERN CWFA
SHOULD MOVE EASTWARD ACROSS THE CWFA GRADUALLY DIMINISHING IN
INTENSITY AS INSTABILITY WANES. GENERALLY CHANGED POPS TO REFLECT
THIS WAVE OF ACTIVITY BEING FOLLOWED BY MUCH LOWER POPS IN SCHC TO
LOW CHC RANGE DUE TO CONTINUED PRESENCE OF UPSTREAM ACTIVITY.
ADJUSTED TEMPERATURE TRENDS FURTHER BY LOWERING TEMPS ACROSS THE
NORTH CAROLINA PIEDMONT DUE TO OUTFLOW BOUNDARIES FROM EARLIER
CONVECTION SPREADING ACROSS THIS REGION.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF 800 PM...TOUCHED UP EVENING TEMP TRENDS...WHICH HAVE BEEN
IMPACTED GREATLY BY THUNDERSTORMS AND THEIR COOL OUTFLOW. RADAR
INDICATES SEVERAL BOUNDARIES SPREADING ACROSS THE PIEDMONT...WHERE
TEMPS REMAIN IN THE MID TO UPPER 70S. THINK THESE WILL BE IMPACTED
BY BOTH DIURNAL COOLING AS WELL AS THE OUTFLOW. LAMP TEMPS SEEM TO
REFLECT THE CURRENT SITUATION FAIRLY WELL AND THESE ARE IN DECENT
AGREEMENT WITH LATE EVENING TEMPS...SO NO CHANGES MADE OTHER THAN TO
UPDATE FIRST FEW HRS.
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
A FEW DEGREES COOLER.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...ANOTHER LINE OF THUNDERSTORMS WILL CROSS THE FIELD
SHORTLY...THEN ACTIVITY WILL DIMINISH. A DAMP AIR MASS AND PRIOR
RAINFALL AMOUNTS SUPPORT VSBY AND CIG RESTRICTIONS TOWARD DAWN...AND
MVFR WILL BE CARRIED. SW WINDS WILL MIX OUT RESTRICTIONS AFTER IN
THE MORNING. ANOTHER ROUND OF CONVECTION WITH POSSIBLE RESTRICTIONS
IS EXPECTED ON THURSDAY AS A COLD FRONT MOVES THROUGH FROM THE
W...AND ANOTHER APPROACHES FROM THE NW. CONVECTION WILL MOVE OFF TO
THE EAST BY THURSDAY EVENING....WHILE SW WINDS VEER TO NW AND BECOME
GUSTY.
ELSEWHERE...CONVECTION WILL MOVE EAST OUR OF THE FOOTHILLS SHORTLY.
EARLIER RAINFALL HAS MOISTENED THE ATMOSPHERE AND GROUND TO THE
POINT THAT AT LEAST MVFR RESTRICTIONS ARE EXPECTED BY DAYBREAK...AND
TEMPORARY IFR AT KAVL. BY MID MORNING RESTRICTIONS WILL END AS THE
WINDS COMES UP FROM THE SW IN THE FOOTHILLS ND NW IN THE MOUNTAINS.
ADDITIONAL CONVECTION AND RESTRICTIONS ARE EXPECTED BY MIDDAY
BETWEEN A DEPARTING COLD FRONT...AND ANOTHER STRONGER FRONT ARRIVING
FROM THE NW. WINDS WILL VEER TO THE WEST DURING THE DAY IN THE
FOOTHILLS AND BECOME GUSTY...VEERING FURTHER TO BECOME NW IN THE
EVENING. PRECIPITATION WILL BE MAINLY CONFINED TO THE MOUNTAINS
THURSDAY EVENING IN NW UPSLOPE FLOW.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
KCLT HIGH 84% HIGH 90% HIGH 100% HIGH 100%
KGSP MED 79% HIGH 88% HIGH 100% HIGH 100%
KAVL MED 70% HIGH 88% HIGH 100% HIGH 97%
KHKY LOW 56% HIGH 83% HIGH 100% HIGH 100%
KGMU MED 73% HIGH 83% HIGH 100% HIGH 100%
KAND MED 69% HIGH 94% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...CDG/JAT/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...JAT
000
FXUS62 KCAE 230351
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1151 PM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
HIGH RESOLUTION WRF INDICATES THUNDERSTORMS MOVING INTO THE AREA
FROM THE WEST WILL DIMINISH. RADAR TRENDS SUPPORT THIS. CLOUDINESS
SHOULD HELP HOLD UP TEMPERATURES. THE TEMPERATURE FORECAST APPEARS
ON TRACK.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MID AND UPPER LEVEL TROUGH CROSSING THE EASTERN CONUS DURING THE
SHORT TERM. THE AIR MASS WILL BE UNSTABLE WITH A PRE-FRONTAL TROUGH
OVER THE MIDLANDS. LOW LEVEL MOISTURE LINGERS WITH PRECIPITABLE
WATER RANGING FROM 1.00 T0 1.75 INCHES. THE THREAT OF CONVECTION
WILL CONTINUE WITH THE HIGHEST CHANCE ACROSS THE EAST MIDLANDS.
WILL RANGE POPS FROM NEAR 30 PERCENT CSRA TO 60 PERCENT NORTHEAST
ON THURSDAY. ALTHOUGH THE GFS IS SLIGHTLY FASTER...MODELS INDICATE
THE COLD FRONT CROSSING THE AREA THURSDAY NIGHT WITH THE CHANCE OF
CONVECTION ENDING. CUT POPS AFTER 18Z FROM PREVIOUS FORECAST BASED
ON LATEST MODEL TRENDS.
THE TEMPERATURE GUIDANCE WAS CLOSE WITH HIGHS IN THE MID/UPPER 80S
AND LOWS IN THE LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
THROUGH WEDNESDAY. GFS ENSEMBLE INCREASE POPS SLIGHTLY THROUGH THE
MIDDLE OF NEXT WEEK. WILL KEEP THE FORECAST DRY GIVEN INCREASING
H500 HEIGHTS AS THE UPPER RIDGE BUILDS.
EXPECT BELOW NORMAL TEMPERATURES DURING THE WEEKEND AND NEAR NORMAL
DURING THE REST OF THE MEDIUM RANGE PERIOD.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
RADAR CURRENTLY INDICATES CONVECTIVE ACTIVITY AT A MINIMUM ACROSS
OUR FA. MOST ACTIVITY CURRENTLY CONFINED TO THE UPSTATE
SC...STRETCHING SW ACROSS NE AND CENT GA. THIS ACTIVITY MOVING
SLOWLY TO THE ENE. LATEST HIGH RES MODELS SUGGEST THE ACTIVITY WILL
GRADUALLY WEAKEN AND DISSIPATE AS IT APPROACHES THE CSRA. FOR
NOW...NOT ENOUGH CONFIDENCE TO MENTION PRECIP IN AGS/DNL TAFS...BUT
WILL MONITOR.
GUIDANCE ALSO CONTINUING TO INDICATE CIG RESTRICTIONS LATE
TONIGHT/EARLY THURSDAY MORNING...IN A CONTINUED MOIST SOUTHERLY LOW
LEVEL FLOW. FOR NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL
MONITOR LATEST GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED.
UPPER IMPULSE AND SURFACE TROUGH WILL MOVE THROUGH
THURSDAY...POSSIBLY LEADING TO SCT SHRA/TSRA. CURRENT THINKING IS
THAT MOST OF THE ACTIVITY THURSDAY WILL BE EAST OF THE TERMINALS.
WILL NOT MENTION IN THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 230251
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1050 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
THERE ARE SOME CHANGES THAT WILL TAKE PLACE IN THE LARGER
SCALE...AS THE FIRST SHORT WAVE OFF THE EASTERN FLORIDA COAST WILL
GET LIFTED NE AS THE NEXT LONG WAVE TROUGH IN THE MISSISSIPPI VALLEY
SHIFTS EAST. IN ADVANCE OF THE LONG WAVE IS A DECENT SHORT WAVE
MOVING THROUGH NE AND CENTRAL GA THAT WILL APPROACH OUR BORDER LATE.
AS THIS TRANSPIRES...IT FORCES THE LAST GRIPS OF THE ATLANTIC RIDGE
TO PULL OFFSHORE AFTER MIDNIGHT...AS A PRE-FRONTAL TROUGH IN WESTERN
GEORGIA APPROACHES LATE. THE FORECAST AREA WILL THEN LIE SANDWICHED
BETWEEN THE FIRST SHORT WAVE IN THE NEARBY ATLANTIC AND THE SECOND
IMPULSE AND ITS REFLECTION AT THAT SURFACE. WHILE THERE IS SOME
INCREASE IN LOW LEVEL CONVERGENCE TO THE EAST...THE SYNOPTIC FLOW
MAY VEER TOO FAR TO THE SW TO ALLOW FOR ANYTHING MORE THAN LOW END
POPS OVER CHARLESTON COUNTY CLOSE TO DAYBREAK. UPSTREAM IT APPEARS
THAT THE BEST FORCING WILL STAY TO THE WEST...BUT A FEW SHOWERS OR
T-STORMS COULD SNEAK INTO THE SW CORNER LATE. FOR NOW WE HAVE SHOWN
POPS AT 14 PERCENT OR LESS FOR ALL BUT NORTHERN CHARLESTON COUNTY
AND CANDLER AND JENKINS WHERE 20 POPS WILL BE SUFFICIENT.
WHILE CONDITIONS ARE NOT AS FAVORABLE FOR FOG DEVELOPMENT AS LAST
NIGHT /IE. TOO MUCH WIND IN THE BOUNDARY LAYER UNTIL LATE AND
MUCH LESS RAINFALL/...WE HAVE MAINTAINED MENTION OF PATCHY FOG TO
OUR NW TIER WHERE THEY HAVE A BETTER CHANCE OF ACHIEVING THEIR
CROSS-OVER TEMPS AND FOG STABILITY INDICES ARE IN THE LOWER 20S.
THE MIXING IN THE BOUNDARY LAYER AND AN INCREASE IN CLOUD COVER
WILL LIMIT TEMPS TO ONLY THE MID AND UPPER 60S INLAND FROM THE
SLIGHTLY WARMER BEACHES.
FOR THOSE THAT ARE INTERESTED...TEMPS AGAIN FAILED TO HIT 90
DEGREES AT BOTH KCHS AND KSAV WEDNESDAY. THIS CONTINUES THE
STRETCH OF SUB-90 DEGREE DAYS AT 257 STRAIGHT AT KCHS AND 256
STRAIGHT AT KSAV DATING BACK TO EARLY SEPTEMBER 2012.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
WHILE WE HAVE MAINTAINED PREVAILING VFR THROUGH 00Z FRIDAY...THERE
IS THE RISK OF MVFR CONDITIONS IN LIGHT FOG/STRATUS A FEW HOURS
EITHER SIDE OF DAYBREAK...AND ALSO MARGINAL MVFR CONDITIONS IN
ISOLATED TO SCATTERED SHRA/TSRA WITH A PRE-FRONTAL TROUGH IN THE
LATE MORNING THROUGH MID AFTERNOON. IF THE TROUGH IS QUICKER THAN
ANTICIPATED THERE COULD BE SOME GUSTY WINDS LATE IN THE TAF CYCLE.
EXTENDED AVIATION...VFR. WINDS COULD GET A BIT GUSTY FRIDAY AFTERNOON
BEHIND THE SECONDARY FRONT.
&&
.MARINE...
TONIGHT...THE SUB TROPICAL RIDGE IN THE ATLANTIC CENTERED OUT NEAR
32N AND 60W WILL START TO RELAX ITS GRIP ACROSS THE COASTAL WATERS
LATE...AS IT STARTS TO GIVE WAY TO AN UPSTREAM PRE-FRONTAL TROUGH.
THE PRESSURE GRADIENT WILL TEMPORARILY TIGHTEN A BIT BETWEEN THESE
TWO FEATURES...ALLOWING FOR SE AND SOUTH WINDS UP TO 15 KT THROUGH
ABOUT 06-08Z...BEFORE VEERING ABOUT 10-30 DEGREES AND DROPPING
OFF TO 10 OR LESS LATE. SEAS WON/T CHANGE MUCH...AVERAGING 2-4 FT
AND HIGHEST ACROSS THE OUTER GA WATERS. WE/LL NEED TO MONITOR FOR
SOME GUSTY SHOWERS/T-STORMS OVERNIGHT AS LOW LEVEL CONVERGENCE
INCREASES.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KGSP 230248
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1048 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 1045 PM...BROKEN MULTICELL LINE OF THUNDERSTORMS CONTINUES TO
MOVE TO THE EAST NORTHEAST ACROSS THE UPSTATE IN ASSOCIATION WITH
CONVERGENCE NEAR FRONTAL BOUNDARY. ELSEWHERE...DISCRETE PULSE
SHOWERS AND THUNDERSTORMS WERE PRESENT ACROSS PORTIONS OF THE NORTH
CAROLINA FOOTHILLS/PIEDMONT. THE MAIN THREATS WITH ANY OF THESE
THUNDERSTORMS ARE BRIEF HEAVY RAINFALL...LARGE HAIL...DAMAGING
WINDS...AND FREQUENT CLOUD TO GROUND LIGHTNING. AS FOR THE
FCST...THE ACTIVITY CURRENTLY EXTENDING ACROSS THE WESTERN CWFA
SHOULD MOVE EASTWARD ACROSS THE CWFA GRADUALLY DIMINISHING IN
INTENSITY AS INSTABILITY WANES. GENERALLY CHANGED POPS TO REFLECT
THIS WAVE OF ACTIVITY BEING FOLLOWED BY MUCH LOWER POPS IN SCHC TO
LOW CHC RANGE DUE TO CONTINUED PRESENCE OF UPSTREAM ACTIVITY.
ADJUSTED TEMPERATURE TRENDS FURTHER BY LOWERING TEMPS ACROSS THE
NORTH CAROLINA PIEDMONT DUE TO OUTFLOW BOUNDARIES FROM EARLIER
CONVECTION SPREADING ACROSS THIS REGION.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF 800 PM...TOUCHED UP EVENING TEMP TRENDS...WHICH HAVE BEEN
IMPACTED GREATLY BY THUNDERSTORMS AND THEIR COOL OUTFLOW. RADAR
INDICATES SEVERAL BOUNDARIES SPREADING ACROSS THE PIEDMONT...WHERE
TEMPS REMAIN IN THE MID TO UPPER 70S. THINK THESE WILL BE IMPACTED
BY BOTH DIURNAL COOLING AS WELL AS THE OUTFLOW. LAMP TEMPS SEEM TO
REFLECT THE CURRENT SITUATION FAIRLY WELL AND THESE ARE IN DECENT
AGREEMENT WITH LATE EVENING TEMPS...SO NO CHANGES MADE OTHER THAN TO
UPDATE FIRST FEW HRS.
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
A FEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AT KCLT...PREVAILING VFR THIS EVENING BUT THERE REMAINS THE
POSSIBILITY OF RESTRICTIONS FROM THUNDERSTORMS. STABILIZING OUTFLOW
FROM UPSTREAM TS MAY PUT A STOP TO CONVECTION BUT ITS LEADING EDGE
COULD BE THE FOCUS FOR NEW DEVELOPMENT FOR A TIME TONIGHT. INCLUDED
A TEMPO THRU 04Z FOR MVFR TSRA...BUT WILL CLOSELY WATCH TRENDS OVER
NEXT COUPLE OF HOURS AND MAY BE ABLE TO REMOVE IT. PROFILES BECOME
INCREASINGLY MOIST OVERNIGHT AHEAD OF FRONTAL BOUNDARY. PER MODEL RH
FIELDS EXPECT A LOWERING TO SOLID MVFR LATE...WITH SUFFICIENT
ELEVATED INSTABILITY TO WARRANT ANOTHER TEMPO FOR TSRA. LULL IN
ACTIVITY EXPECTED NEAR DAYBREAK WITH LOW MVFR PERSISTING UNTIL
MIXING GETS UNDERWAY MID MORNING. DECENT THUNDER CHANCES AGAIN WITH
DIURNAL HEATING WARRANTING -TSRA BUT VFR.
ELSEWHERE...CONVECTION CONTINUES THIS EVENING ACROSS MAINLY THE
MTNS/FOOTHILLS. MUCH OF THE PIEDMONT WILL BE STABILIZED BY TS
OUTFLOW WITH UPSTREAM ACTIVITY LIKELY TO DIMINISH TOO QUICKLY WITH
LOSS OF HEATING TO HAVE EFFECTS. OVERNIGHT FROPA WILL BRING BACK TS
OR SHRA CHANCES. HANDLED THIS WITH VCTS OR TEMPOS AS APPROPRIATE.
PLENTY OF MOISTURE TO THINK RESTRICTIVE CIGS WILL DEVELOP BEHIND THE
FRONT AND PERSIST THRU DAYBREAK. DIURNAL CU WILL QUICKLY GROW IN
UNSTABLE ATMOSPHERE BY LATE MORNING. CU BASES EXPECTED TO BE WELL
WITHIN VFR TERRITORY...WITH SOME LOW TS CHANCES ALSO THROUGH PEAK
HEATING.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT MED 60% HIGH 86% HIGH 80% HIGH 100%
KGSP LOW 58% MED 72% HIGH 82% HIGH 100%
KAVL MED 71% HIGH 97% HIGH 98% HIGH 100%
KHKY LOW 45% MED 77% HIGH 91% HIGH 100%
KGMU LOW 58% MED 73% HIGH 100% HIGH 100%
KAND MED 65% MED 76% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...CDG/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...CDG/WIMBERLEY
000
FXUS62 KCAE 230211
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1011 PM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA INTENSIFYING PAST COUPLE
OF HOURS IN AREA OF STRONG INSTABILITY. LIFT ENHANCED BY
APPROACHING SHORT WAVE TROUGH NOW MOVING INTO WESTERN GEORGIA.
CONVECTION MAY MOVE INTO WESTERN CSRA/PIEDMONT THIS EVENING. WILL
INCREASE POPS IN THAT AREA. DECREASED POPS ACROSS REST OF REGION
WITH LITTLE FORCING FOR CONVECTION THIS EVENING.
SKIES WILL BECOME MOSTLY CLOUDY TONIGHT WITH SOME LOW CLOUDS
EXPECTED. FRONT APPROACHING LATE CANT RULE OUT A SHOWERS LATE
TONIGHT...BUT SHOULD REMAIN ISOLATED. OVERNIGHT LOWS WILL
GENERALLY BE IN THE MID 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MID AND UPPER LEVEL TROUGH CROSSING THE EASTERN CONUS DURING THE
SHORT TERM. THE AIR MASS WILL BE UNSTABLE WITH A PRE-FRONTAL TROUGH
OVER THE MIDLANDS. LOW LEVEL MOISTURE LINGERS WITH PRECIPITABLE
WATER RANGING FROM 1.00 T0 1.75 INCHES. THE THREAT OF CONVECTION
WILL CONTINUE WITH THE HIGHEST CHANCE ACROSS THE EAST MIDLANDS.
WILL RANGE POPS FROM NEAR 30 PERCENT CSRA TO 60 PERCENT NORTHEAST
ON THURSDAY. ALTHOUGH THE GFS IS SLIGHTLY FASTER...MODELS INDICATE
THE COLD FRONT CROSSING THE AREA THURSDAY NIGHT WITH THE CHANCE OF
CONVECTION ENDING. CUT POPS AFTER 18Z FROM PREVIOUS FORECAST BASED
ON LATEST MODEL TRENDS.
THE TEMPERATURE GUIDANCE WAS CLOSE WITH HIGHS IN THE MID/UPPER 80S
AND LOWS IN THE LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
THROUGH WEDNESDAY. GFS ENSEMBLE INCREASE POPS SLIGHTLY THROUGH THE
MIDDLE OF NEXT WEEK. WILL KEEP THE FORECAST DRY GIVEN INCREASING
H500 HEIGHTS AS THE UPPER RIDGE BUILDS.
EXPECT BELOW NORMAL TEMPERATURES DURING THE WEEKEND AND NEAR NORMAL
DURING THE REST OF THE MEDIUM RANGE PERIOD.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
RADAR CURRENTLY INDICATES CONVECTIVE ACTIVITY AT A MINIMUM ACROSS
OUR FA. MOST ACTIVITY CURRENTLY CONFINED TO THE UPSTATE
SC...STRETCHING SW ACROSS NE AND CENT GA. THIS ACTIVITY MOVING
SLOWLY TO THE ENE. LATEST HIGH RES MODELS SUGGEST THE ACTIVITY WILL
GRADUALLY WEAKEN AND DISSIPATE AS IT APPROACHES THE CSRA. FOR
NOW...NOT ENOUGH CONFIDENCE TO MENTION PRECIP IN AGS/DNL TAFS...BUT
WILL MONITOR.
GUIDANCE ALSO CONTINUING TO INDICATE CIG RESTRICTIONS LATE
TONIGHT/EARLY THURSDAY MORNING...IN A CONTINUED MOIST SOUTHERLY LOW
LEVEL FLOW. FOR NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL
MONITOR LATEST GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED.
UPPER IMPULSE AND SURFACE TROUGH WILL MOVE THROUGH
THURSDAY...POSSIBLY LEADING TO SCT SHRA/TSRA. CURRENT THINKING IS
THAT MOST OF THE ACTIVITY THURSDAY WILL BE EAST OF THE TERMINALS.
WILL NOT MENTION IN THE TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KCHS 230201
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1000 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
THERE ARE SOME CHANGES THAT WILL TAKE PLACE IN THE LARGER
SCALE...AS THE FIRST SHORT WAVE OFF THE EASTERN FLORIDA COAST WILL
GET LIFTED NE AS THE NEXT LONG WAVE TROUGH IN THE MISSISSIPPI
VALLEY SHIFTS EAST. AS THIS TRANSPIRES...IT FORCES THE LAST GRIPS
OF THE ATLANTIC RIDGE TO PULL OFFSHORE AFTER MIDNIGHT...AS A PRE-
FRONTAL TROUGH IN WESTERN GEORGIA APPROACHES LATE. THE FORECAST
AREA WILL THEN LIE SANDWICHED BETWEEN THE FIRST SHORT WAVE IN THE
NEARBY ATLANTIC AND THE SECOND IMPULSE AND ITS REFLECTION AT THAT
SURFACE. WHILE THERE IS SOME INCREASE IN LOW LEVEL CONVERGENCE TO
THE EAST...THE SYNOPTIC FLOW MAY VEER TOO FAR TO THE SW TO ALLOW
FOR ANYTHING MORE THAN LOW END POPS OVER CHARLESTON COUNTY CLOSE
TO DAYBREAK. UPSTREAM IT APPEARS THAT THE BEST FORCING WILL STAY
TO THE WEST...BUT A FEW SHOWERS OR T-STORMS COULD SNEAK INTO THE SW
CORNER LATE. FOR NOW WE HAVE SHOWN POPS AT 14 PERCENT OR LESS FOR
ALL BUT NORTHERN CHARLESTON COUNTY AND CANDLER AND JEKINS WHERE 20
POPS WILL BE SUFFICIENT.
WHILE CONDITIONS ARE NOT AS FAVORABLE FOR FOG DEVELOPMENT AS LAST
NIGHT /IE. TOO MUCH WIND IN THE BOUNDARY LAYER UNTIL LATE AND
MUCH LESS RAINFALL/...WE HAVE MAINTAINED MENTION OF PATCHY FOG TO
OUR NW TIER WHERE THEY HAVE A BETTER CHANCE OF ACHIEVING THEIR
CROSS-OVER TEMPS AND FOG STABILITY INDICES ARE IN THE LOWER 20S.
THE MIXING IN THE BOUNDARY LAYER AND AN INCREASE IN CLOUD COVER
WILL LIMIT TEMPS TO ONLY THE MID AND UPPER 60S INLAND FROM THE
SLIGHTLY WARMER BEACHES.
FOR THOSE THAT ARE INTERESTED...TEMPS AGAIN FAILED TO HIT 90
DEGREES AT BOTH KCHS AND KSAV WEDNESDAY. THIS CONTINUES THE
STRETCH OF SUB-90 DEGREE DAYS AT 257 STRAIGHT AT KCHS AND 256
STRAIGHT AT KSAV DATING BACK TO EARLY SEPTEMBER 2012.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
WHILE WE HAVE MAINTAINED PREVAILING VFR THROUGH 00Z FRIDAY...THERE
IS THE RISK OF MVFR CONDITIONS IN LIGHT FOG/STRATUS A FEW HOURS
EITHER SIDE OF DAYBREAK...AND ALSO MARGINAL MVFR CONDITIONS IN
ISOLATED TO SCATTERED SHRA/TSRA WITH A PRE-FRONTAL TROUGH IN THE
LATE MORNING THROUGH MID AFTERNOON. IF THE TROUGH IS QUICKER THAN
ANTICIPATED THERE COULD BE SOME GUSTY WINDS LATE IN THE TAF CYCLE.
EXTENDED AVIATION...VFR. WINDS COULD GET A BIT GUSTY FRIDAY AFTERNOON
BEHIND THE SECONDARY FRONT.
&&
.MARINE...
TONIGHT...THE SUB TROPICAL RIDGE IN THE ATLANTIC CENTERED OUT NEAR
32N AND 60W WILL START TO RELAX ITS GRIP ACROSS THE COASTAL WATERS
LATE...AS IT STARTS TO GIVE WAY TO AN UPSTREAM PRE-FRONTAL TROUGH.
THE PRESSURE GRADIENT WILL TEMPORARILY TIGHTEN A BIT BETWEEN THESE
TWO FEATURES...ALLOWING FOR SE AND SOUTH WINDS UP TO 15 KT THROUGH
ABOUT 06-08Z...BEFORE VEERING ABOUT 10-30 DEGREES AND DROPPING
OFF TO 10 OR LESS LATE. SEAS WON/T CHANGE MUCH...AVERAGING 2-4 FT
AND HIGHEST ACROSS THE OUTER GA WATERS. WE/LL NEED TO MONITOR FOR
SOME GUSTY SHOWERS/T-STORMS OVERNIGHT AS LOW LEVEL CONVERGENCE
INCREASES.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCHS 230151
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
951 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
THERE ARE SOME CHANGES THAT WILL TAKE PLACE IN THE LARGER
SCALE...AS THE FIRST SHORT WAVE OFF THE EASTERN FLORIDA COAST WILL
GET LIFTED NE AS THE NEXT LONG WAVE TROUGH IN THE MISSISSIPPI
VALLEY SHIFTS EAST. AS THIS TRANSPIRES...IT FORCES THE LAST GRIPS
OF THE ATLANTIC RIDGE TO PULL OFFSHORE AFTER MIDNIGHT...AS A PRE-
FRONTAL TROUGH IN WESTERN GEORGIA APPROACHES LATE. THE FORECAST
AREA WILL THEN LIE SANDWICHED BETWEEN THE FIRST SHORT WAVE IN THE
NEARBY ATLANTIC AND THE SECOND IMPULSE AND ITS REFLECTION AT THAT
SURFACE. WHILE THERE IS SOME INCREASE IN LOW LEVEL CONVERGENCE TO
THE EAST...THE SYNOPTIC FLOW MAY VEER TOO FAR TO THE SW TO ALLOW
FOR ANYTHING MORE THAN LOW END POPS OVER CHARLESTON COUNTY CLOSE
TO DAYBREAK. UPSTREAM IT APPEARS THAT THE BEST FORCING WILL STAY
TO THE WEST...BUT A FEW SHOWERS OR T-STORMS COULD SNEAK INTO THE
SW CORNER LATE. FOR NOW WE HAVE SHOWN POPS AT 14 PERCENT OR LESS.
WHILE CONDITIONS ARE NOT AS FAVORABLE FOR FOG DEVELOPMENT AS LAST
NIGHT /IE. TOO MUCH WIND IN THE BOUNDARY LAYER UNTIL LATE AND
MUCH LESS RAINFALL/...WE HAVE MAINTAINED MENTION OF PATCHY FOG TO
OUR NW TIER WHERE THEY HAVE A BETTER CHANCE OF ACHIEVING THEIR
CROSS-OVER TEMPS AND FOG STABILITY INDICES ARE IN THE LOWER 20S.
THE MIXING IN THE BOUNDARY LAYER AND AN INCREASE IN CLOUD COVER
WILL LIMIT TEMPS TO ONLY THE MID AND UPPER 60S INLAND FROM THE
SLIGHTLY WARMER BEACHES.
FOR THOSE THAT ARE INTERESTED...TEMPS AGAIN FAILED TO HIT 90
DEGREES AT BOTH KCHS AND KSAV WEDNESDAY. THIS CONTINUES THE
STRETCH OF SUB-90 DEGREE DAYS AT 257 STRAIGHT AT KCHS AND 256
STRAIGHT AT KSAV DATING BACK TO EARLY SEPTEMBER 2012.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
WHILE WE HAVE MAINTAINED PREVAILING VFR THROUGH 00Z FRIDAY...THERE
IS THE RISK OF MVFR CONDITIONS IN LIGHT FOG/STRATUS A FEW HOURS
EITHER SIDE OF DAYBREAK...AND ALSO MARGINAL MVFR CONDITIONS IN
ISOLATED TO SCATTERED SHRA/TSRA WITH A PRE-FRONTAL TROUGH IN THE
LATE MORNING THROUGH MID AFTERNOON. IF THE TROUGH IS QUICKER THAN
ANTICIPATED THERE COULD BE SOME GUSTY WINDS LATE IN THE TAF CYCLE.
EXTENDED AVIATION...VFR. WINDS COULD GET A BIT GUSTY FRIDAY AFTERNOON
BEHIND THE SECONDARY FRONT.
&&
.MARINE...
TONIGHT...THE SUB TROPICAL RIDGE IN THE ATLANTIC CENTERED OUT NEAR
32N AND 60W WILL START TO RELAX ITS GRIP ACROSS THE COASTAL WATERS
LATE...AS IT STARTS TO GIVE WAY TO AN UPSTREAM PRE-FRONTAL TROUGH.
THE PRESSURE GRADIENT WILL TEMPORARILY TIGHTEN A BIT BETWEEN THESE
TWO FEATURES...ALLOWING FOR SE AND SOUTH WINDS UP TO 15 KT THROUGH
ABOUT 06-08Z...BEFORE VEERING ABOUT 10-30 DEGREES AND DROPPING
OFF TO 10 OR LESS LATE. SEAS WON/T CHANGE MUCH...AVERAGING 2-4 FT
AND HIGHEST ACROSS THE OUTER GA WATERS. WE/LL NEED TO MONITOR FOR
SOME GUSTY SHOWERS/T-STORMS OVERNIGHT AS LOW LEVEL CONVERGENCE
INCREASES.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 230022
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
822 PM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA INTENSIFYING PAST COUPLE
OF HOURS IN AREA OF STRONG INSTABILITY. LIFT ENHANCED BY
APPROACHING SHORT WAVE TROUGH NOW MOVING INTO WESTERN GEORGIA.
CONVECTION MAY MOVE INTO WESTERN CSRA/PIEDMONT THIS EVENING. WILL
INCREASE POPS IN THAT AREA. DECREASED POPS ACROSS REST OF REGION
WITH LITTLE FORCING FOR CONVECTION THIS EVENING.
SKIES WILL BECOME MOSTLY CLOUDY TONIGHT WITH SOME LOW CLOUDS
EXPECTED. FRONT APPROACHING LATE CANT RULE OUT A SHOWERS LATE
TONIGHT...BUT SHOULD REMAIN ISOLATED. OVERNIGHT LOWS WILL
GENERALLY BE IN THE MID 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MID AND UPPER LEVEL TROUGH CROSSING THE EASTERN CONUS DURING THE
SHORT TERM. THE AIR MASS WILL BE UNSTABLE WITH A PRE-FRONTAL TROUGH
OVER THE MIDLANDS. LOW LEVEL MOISTURE LINGERS WITH PRECIPITABLE
WATER RANGING FROM 1.00 T0 1.75 INCHES. THE THREAT OF CONVECTION
WILL CONTINUE WITH THE HIGHEST CHANCE ACROSS THE EAST MIDLANDS.
WILL RANGE POPS FROM NEAR 30 PERCENT CSRA TO 60 PERCENT NORTHEAST
ON THURSDAY. ALTHOUGH THE GFS IS SLIGHTLY FASTER...MODELS INDICATE
THE COLD FRONT CROSSING THE AREA THURSDAY NIGHT WITH THE CHANCE OF
CONVECTION ENDING. CUT POPS AFTER 18Z FROM PREVIOUS FORECAST BASED
ON LATEST MODEL TRENDS.
THE TEMPERATURE GUIDANCE WAS CLOSE WITH HIGHS IN THE MID/UPPER 80S
AND LOWS IN THE LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
THROUGH WEDNESDAY. GFS ENSEMBLE INCREASE POPS SLIGHTLY THROUGH THE
MIDDLE OF NEXT WEEK. WILL KEEP THE FORECAST DRY GIVEN INCREASING
H500 HEIGHTS AS THE UPPER RIDGE BUILDS.
EXPECT BELOW NORMAL TEMPERATURES DURING THE WEEKEND AND NEAR NORMAL
DURING THE REST OF THE MEDIUM RANGE PERIOD.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
RADAR INDICATES CONVECTIVE ACTIVITY AT A MINIMUM ACROSS OUR FA. MOST
ACTIVITY CURRENTLY CONFINED TO THE UPSTATE SC AND N/CENT GA. HIGH
RES MODELS INDICATE ACTIVITY DEVELOPING TO OUR WEST NEAR AN UPPER
IMPULSE AND SURFACE TROUGH...WEAKENING AS IT MOVES EAST AND
APPROACHES THE FA LATE TONIGHT. GUIDANCE INDICATING CIG RESTRICTIONS
LATE TONIGHT...IN A CONTINUED MOIST SOUTHERLY LOW LEVEL FLOW. FOR
NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL MONITOR LATEST
GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED. UPPER IMPULSE
AND SURFACE TROUGH WILL MOVE THROUGH THURSDAY...POSSIBLY LEADING
TO SCT SHRA/TSRA...BUT CHANCES TOO LOW...ALONG WITH SOME TIMING
QUESTIONS...TO INCLUDE MENTION IN THE TAF AT THIS TIME.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
000
FXUS62 KGSP 230022
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
822 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 800 PM...TOUCHED UP EVENING TEMP TRENDS...WHICH HAVE BEEN
IMPACTED GREATLY BY THUNDERSTORMS AND THEIR COOL OUTFLOW. RADAR
INDICATES SEVERAL BOUNDARIES SPREADING ACROSS THE PIEDMONT...WHERE
TEMPS REMAIN IN THE MID TO UPPER 70S. THINK THESE WILL BE IMPACTED
BY BOTH DIURNAL COOLING AS WELL AS THE OUTFLOW. LAMP TEMPS SEEM TO
REFLECT THE CURRENT SITUATION FAIRLY WELL AND THESE ARE IN DECENT
AGREEMENT WITH LATE EVENING TEMPS...SO NO CHANGES MADE OTHER THAN TO
UPDATE FIRST FEW HRS.
AS OF 430 PM...INCREASED POPS ACROSS THE UPSTATE OF SOUTH CAROLINA
AND THE PIEDMONT OF NORTH CAROLINA DURING THE OVERNIGHT HOURS AS
SHORT TERM CONVECTIVE MODEL GUIDANCE CONTINUES WIDESPREAD CONVECTION
ACROSS THE ABOVE MENTIONED REGIONS THROUGH 10Z THURSDAY. ALSO
TOUCHED UP SKY AND TEMP GRIDS. OTHERWISE...NO OTHER CHANGES WERE
MADE.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
A FEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
AT KCLT...PREVAILING VFR THIS EVENING BUT THERE REMAINS THE
POSSIBILITY OF RESTRICTIONS FROM THUNDERSTORMS. STABILIZING OUTFLOW
FROM UPSTREAM TS MAY PUT A STOP TO CONVECTION BUT ITS LEADING EDGE
COULD BE THE FOCUS FOR NEW DEVELOPMENT FOR A TIME TONIGHT. INCLUDED
A TEMPO THRU 04Z FOR MVFR TSRA...BUT WILL CLOSELY WATCH TRENDS OVER
NEXT COUPLE OF HOURS AND MAY BE ABLE TO REMOVE IT. PROFILES BECOME
INCREASINGLY MOIST OVERNIGHT AHEAD OF FRONTAL BOUNDARY. PER MODEL RH
FIELDS EXPECT A LOWERING TO SOLID MVFR LATE...WITH SUFFICIENT
ELEVATED INSTABILITY TO WARRANT ANOTHER TEMPO FOR TSRA. LULL IN
ACTIVITY EXPECTED NEAR DAYBREAK WITH LOW MVFR PERSISTING UNTIL
MIXING GETS UNDERWAY MID MORNING. DECENT THUNDER CHANCES AGAIN WITH
DIURNAL HEATING WARRANTING -TSRA BUT VFR.
ELSEWHERE...CONVECTION CONTINUES THIS EVENING ACROSS MAINLY THE
MTNS/FOOTHILLS. MUCH OF THE PIEDMONT WILL BE STABILIZED BY TS
OUTFLOW WITH UPSTREAM ACTIVITY LIKELY TO DIMINISH TOO QUICKLY WITH
LOSS OF HEATING TO HAVE EFFECTS. OVERNIGHT FROPA WILL BRING BACK TS
OR SHRA CHANCES. HANDLED THIS WITH VCTS OR TEMPOS AS APPROPRIATE.
PLENTY OF MOISTURE TO THINK RESTRICTIVE CIGS WILL DEVELOP BEHIND THE
FRONT AND PERSIST THRU DAYBREAK. DIURNAL CU WILL QUICKLY GROW IN
UNSTABLE ATMOSPHERE BY LATE MORNING. CU BASES EXPECTED TO BE WELL
WITHIN VFR TERRITORY...WITH SOME LOW TS CHANCES ALSO THROUGH PEAK
HEATING.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT MED 60% MED 78% MED 79% HIGH 96%
KGSP LOW 57% MED 65% MED 73% HIGH 100%
KAVL HIGH 80% HIGH 94% HIGH 94% HIGH 100%
KHKY LOW 58% MED 60% HIGH 82% HIGH 100%
KGMU LOW 57% MED 68% HIGH 91% HIGH 100%
KAND MED 65% HIGH 86% HIGH 91% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...CDG/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...CDG/WIMBERLEY
000
FXUS62 KGSP 222355
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
755 PM EDT WED MAY 22 2013
.SYNOPSIS...
AN APPROACHING UPPER LEVEL TROUGH WILL CONTINUE TO INFLUENCE THE
REGION THROUGH THURSDAY. A COLD FRONT MOVES THROUGH THE AREA
THURSDAY NIGHT...BEFORE A COOLER AND DRIER AIRMASS SETTLES IN FOR
THE WEEKEND AND MODIFIES THROUGH THE EARLY PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 430 PM...INCREASED POPS ACROSS THE UPSTATE OF SOUTH CAROLINA
AND THE PIEDMONT OF NORTH CAROLINA DURING THE OVERNIGHT HOURS AS
SHORT TERM CONVECTIVE MODEL GUIDANCE CONTINUES WIDESPREAD CONVECTION
ACROSS THE ABOVE MENTIONED REGIONS THROUGH 10Z THURSDAY. ALSO
TOUCHED UP SKY AND TEMP GRIDS. OTHERWISE...NO OTHER CHANGES WERE
MADE.
REMAINDER OF PREVIOUS DISCUSSION...
AS OF MID AFTERNOON...A BROKEN BAND OF SHOWERS AND THUNDERSTORMS WAS
LOCATED JUST EAST OF THE BLUE RIDGE IN NC FROM I-40 NEWD...WITH
OTHER STORMS POPPING UP ACROSS THE HIGHER TERRAIN AIDED BY
DIFFERENTIAL HEATING. EXPECT THE STORMS TO BECOME MORE NUMEROUS
ACROSS THE MTNS THROUGH LATE AFTERNOON...WITH THAT CONVECTION MOVING
EAST OVER THE FOOTHILLS AND PIEDMONT INTO THE EVENING. POP HAS BEEN
ADJUSTED ACCORDINGLY. SOME OF THESE STORMS WILL PRODUCE LARGE HAIL
AND DAMAGING WIND GUSTS. HIGH TEMPS STILL LOOK OKAY.
FOR TONIGHT...THE CONVECTION ALLOWING MODELS SUGGEST THAT ANOTHER
ROUND OF STORMS WILL FIRE TO THE WEST AND THEN MOVE EAST INTO THE
FCST AREA IN THE EARLY EVENING. THE HRRR AND 4KM WRF PAINT A SIMILAR
PICTURE WITH NUMEROUS STORMS OVER THE WESTERN HALF OF THE FCST AREA
THROUGH MID TO LATE EVENING. A SHORT WAVE MOVING AROUND THE UPPER
TROF...COMBINED WITH SOME UPPER DIVERGENCE...SHOULD PROVIDE THE
NECESSARY SUPPORT FOR THIS CONVECTION TO THRIVE. WITH THAT IN
MIND...THE POP WAS RAISED TO LIKELY OVER THE WESTERN HALF. AFTER
SOME LOSS OF HEATING...THE STORMS SHOULD BECOME A BIT LESS NUMEROUS
OVER THE NC PIEDMONT. AT THAT POINT...THE POP WAS KEPT BELOW 50 PCT
ONLY BECAUSE OF SOME UNCERTAINTY GIVEN BY THE CONVECTION HAVING NOT
YET DEVELOPED AS OF 18Z. MIN TEMPS SHOULD REMAIN MILD.
THE COLD FRONT WILL MOVE IN FROM THE WEST ON THURSDAY...MOST LIKELY
OVER THE MTNS IN THE MORNING AND THEN MOVING OUT OVER THE FOOTHILLS
IN THE AFTERNOON. NEW CONVECTION SHOULD DEVELOP ALONG THE FRONT
MAINLY OVER THE PIEDMONT IN THE AFTERNOON. THIS IS TRICKY BECAUSE OF
THE LIKELIHOOD OF WIDESPREAD DEBRIS CLOUDINESS INTO THE EARLY
AFTERNOON THAT WOULD LIMIT CONVECTION. THINK THE MTNS STAND A CHANCE
BECAUSE OF THE FRONT EARLY IN THE DAY. THE UPSTATE AND NE GEORGIA
HAS THE LEAST FAVORABLE ENVIRONMENT...SO A 20 PCT POP WAS KEPT. THE
PIEDMONT HAS A BETTER CHANCE AHEAD OF THE FRONT SO A LIKELY POP WAS
CARRIED OVER THE EASTERN ZONES FOR A TIME. SEVERE STORMS ARE
POSSIBLE...BUT MORE LIKELY TO THE EAST OF I-77. HIGH TEMPS WILL BE
AFEW DEGREES COOLER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM WEDNESDAY...A SURFACE COLD FRONT SHOULD BE LOCATED NEAR
THE EDGE OF OUR WESTERN NORTH CAROLINA PIEDMONT EARLY THURSDAY
EVENING. THIS LINES UP WELL WITH THE SHORT TERM SUITE OF MODELS...
AND LINES UP WITH WITH AN AXIS OF DPVA WHICH SHOULD BE CROSSING THAT
REGION LATE IN THE DAY/EARLY EVENING. CONVECTIVE ALLOWING MODELS
ALSO DEPICT THIS TREND AND IS SUPPORTED BY INSTABILITY LINGERING
ACROSS THAT AREA. AS A RESULT WE WILL HAVE A CORRIDOR OF LOWER
CHANCE POPS IN OUR EASTERN FORECAST AREA (FA) UNTIL AROUND DARK OR
SO.
A SECOND AREA OF PRECIPITATION FOR THURSDAY NIGHT WILL BE IN THE NC
MOUNTAINS WHERE ANOTHER LOBE OF ENERGY...EMBEDDED IN A SHARPENING H5
TROF...CROSSES THE AREA. WE WILL CARRY CHANCE POPS IN THE NC
MOUNTAINS THURSDAY NIGHT AND FRIDAY MORNING...IN A CONTINUALLY
DEEPENING FORCED UPPER AIR PATTERN. ALTHOUGH THE SHARPENING TROF
CROSSES ALL OF OUR REGION FRIDAY...THE ATMOSPHERE LOOKS TO DRY FOR
ANY PRECIPITATION.
MEANWHILE THE H85 ISALLOBARIC PATTERN WAS INDICATING SIGNIFICANT
CROSS CONTOURS OF THERMAL STRUCTURE AND HEIGHTS FRIDAY. THIS
SUGGESTS AT LEAST SIGNIFICANT COLD AIR ADVECTION (ESPECIALLY JUST
ABOVE THE SURFACE) AND MIXING DOWN. WE HAVE FOLLOWED BUFKIT
INFORMATION FOR WIND GUSTS FRIDAY...AND IN ALL LIKELIHOOD WE WILL
NEED SOME TYPE OF WIND HEADLINE FRIDAY FOR PART OF OUR FAA...
PARTICULARLY IN THE AFTERNOON.
HIGH PRESSURE WILL EDGE TOWARD THE REGION FRIDAY NIGHT...WHICH WILL
BRING A COOL/COLD NIGHT AROUND THE AREA. SOME MOUNTAIN LOCATIONS TO
DIP INTO THE 30S...BUT BELIEVE ENOUGH MIXING SHOULD PREVENT FROST
DUE TO THE LINGERING GRADIENT OF HIGH PRESSURE OFF TO THE NORTHWEST
AND LOW PRESSURE MOVING UP THE EASTERN SEABOARD. HOWEVER WE WILL
HAVE TO MONITOR TRENDS.
HIGH PRESSURE TO HOLD SWAY SATURDAY WITH A PLEASANT DAY ON
TAP.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 PM WEDNESDAY...RATHER GOOD AGREEMENT IS HAD IN THE UPPER
LEVEL OMEGA PATTERN OVER THE EXT RANGE. THE 12Z GFS IS A BIT OF AN
OUTLIER AND SHARPENS THE EAST COAST TROF AND SUBSEQUENT DEEP NW/LY
FLOW GRADIENT MORESO THAN THE OTHER OP MODELS...BUT NOT ENOUGH FOR A
SIGFNT LLVL RESPONSE. AT THE SFC...THERE ARE MAJOR DIFFERENCES
EVOLVING WITH THE SYNOPTIC PATTERN...THUS A LESS THAN AVG
CONFIDENCE IS HAD AS THE EXT RANGE PROGRESSES.
HIGH PRESSURE CONTINUES TO BUILD IN FROM THE NORTH SUN AND KEEPS
THINGS DRY. HIGH TEMPS WILL BE A LITTLE BELOW NORMAL WITH A
REINFORCING CP AIRMASS MIXING IN. THE LLVL FLOW BECOMES DEFINED
SW/LY MON AS THE ATL HIGH NUDGES IN. THIS WILL ALSO ENABLE A WARM
FRONT OR STATIONARY TO PERHAPS IMPINGE UPON THE REGION MON NIGHT
INTO TUE. THERE IS LOW CONFIDENCE IN THIS FEATURE...HOWEVER...AS THE
GFS KEEPS ANY FRONTOGENESIS WELL TO THE NORTH OF THE REGION WITH A
WEAK TROF BUILDING INTO THE SFC SE RIDGE...WHILE THE ECMWF HAS THE
WARM FRONT STALLING OUT ACROSS THE CWFA DURING THE DAY TUE INTO WED.
RIGHT NOW...POPS HAVE BEEN CONTINUED IN THE LOW END CHANCE RANGE MON
THROUGH TUE...AND A DRIER HPC BLEND WAS MAINTAINED FOR WED.
SOUNDINGS SHOW VERY LITTLE SBCAPE DEVELOPING MON AS THE UPPER FLOW
KEEPS A SUBSIDENCE INVERSION IN PLACE...HOWEVER A RELATIVE WEAKENING
ALOFT TUE SHOULD ENABLE THE DEVELOPMENT OF SOME ENHANCE CONVECTION
AND TSTMS. MAX TEMPS WILL WARM EACH DAY MON THROUGH THE PERIOD TO A
LITTLE ABOVE NORMAL IN GOOD SW/LY FLOW AND INSOLATION.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AT KCLT...PREVAILING VFR THIS EVENING BUT THERE REMAINS THE
POSSIBILITY OF RESTRICTIONS FROM THUNDERSTORMS. STABILIZING OUTFLOW
FROM UPSTREAM TS MAY PUT A STOP TO CONVECTION BUT ITS LEADING EDGE
COULD BE THE FOCUS FOR NEW DEVELOPMENT FOR A TIME TONIGHT. INCLUDED
A TEMPO THRU 04Z FOR MVFR TSRA...BUT WILL CLOSELY WATCH TRENDS OVER
NEXT COUPLE OF HOURS AND MAY BE ABLE TO REMOVE IT. PROFILES BECOME
INCREASINGLY MOIST OVERNIGHT AHEAD OF FRONTAL BOUNDARY. PER MODEL RH
FIELDS EXPECT A LOWERING TO SOLID MVFR LATE...WITH SUFFICIENT
ELEVATED INSTABILITY TO WARRANT ANOTHER TEMPO FOR TSRA. LULL IN
ACTIVITY EXPECTED NEAR DAYBREAK WITH LOW MVFR PERSISTING UNTIL
MIXING GETS UNDERWAY MID MORNING. DECENT THUNDER CHANCES AGAIN WITH
DIURNAL HEATING WARRANTING -TSRA BUT VFR.
ELSEWHERE...CONVECTION CONTINUES THIS EVENING ACROSS MAINLY THE
MTNS/FOOTHILLS. MUCH OF THE PIEDMONT WILL BE STABILIZED BY TS
OUTFLOW WITH UPSTREAM ACTIVITY LIKELY TO DIMINISH TOO QUICKLY WITH
LOSS OF HEATING TO HAVE EFFECTS. OVERNIGHT FROPA WILL BRING BACK TS
OR SHRA CHANCES. HANDLED THIS WITH VCTS OR TEMPOS AS APPROPRIATE.
PLENTY OF MOISTURE TO THINK RESTRICTIVE CIGS WILL DEVELOP BEHIND THE
FRONT AND PERSIST THRU DAYBREAK. DIURNAL CU WILL QUICKLY GROW IN
UNSTABLE ATMOSPHERE BY LATE MORNING. CU BASES EXPECTED TO BE WELL
WITHIN VFR TERRITORY...WITH SOME LOW TS CHANCES ALSO THROUGH PEAK
HEATING.
OUTLOOK...RESTRICTIONS POSSIBLE WITH LINGERING MOISTURE OVERNIGHT
THU NIGHT AND FRI MORNING. GENERALLY VFR WEATHER FRIDAY AND SATURDAY.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT MED 60% MED 78% MED 79% HIGH 96%
KGSP LOW 57% MED 65% MED 73% HIGH 100%
KAVL HIGH 80% HIGH 94% HIGH 94% HIGH 100%
KHKY LOW 58% MED 60% HIGH 82% HIGH 100%
KGMU LOW 57% MED 68% HIGH 91% HIGH 100%
KAND MED 65% HIGH 86% HIGH 91% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...CDG/PM/WIMBERLEY
SHORT TERM...TS
LONG TERM...SBK
AVIATION...CDG/WIMBERLEY
000
FXUS62 KCHS 222339
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
734 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
QUITE A CHANGE IN THE PATTERN SINCE YESTERDAY...WITH MUCH OF THE
AREA VOID OF ANY CONVECTION EARLIER TODAY. WE/RE FINISHED FOR THE
EVENING FOR ANY SHOWERS OR T-STORMS IN THE LOCAL ZONES...WITH THE
SEA BREEZE HAVING CLEARED OUR NW TIER. IN ITS WAKE A STABILIZED
ENVIRONMENT HAS ENSUED AND WILL PERSIST.
FOR TONIGHT... THERE IS SOME CHANGES THAT WILL TAKE PLACE IN THE
LARGER SCALE...AS THE FIRST SHORT WAVE OFF THE EASTERN FLORIDA COAST
TO GET LIFTED NE AS THE NEXT LONG WAVE TROUGH IN THE MISSISSIPPI
VALLEY SHIFTS EAST. AS THIS TRANSPIRES...IT FORCES THE LAST GRIPS OF
THE ATLANTIC RIDGE TO PULL OFFSHORE AFTER MIDNIGHT...AS A
PRE-FRONTAL TROUGH IN EASTERN ALABAMA AND WESTERN GEORGIA APPROACHES
LATE. THE FORECAST AREA WILL THEN LIE SANDWICHED BETWEEN THE FIRST
SHORT WAVE IN THE NEARBY ATLANTIC AND THE SECOND IMPULSE AND ITS
REFLECTION AT THAT SURFACE. WHILE THERE IS SOME INCREASE IN LOW
LEVEL CONVERGENCE TO THE EAST...THE SYNOPTIC FLOW MAY VEER TOO FAR
TO THE SW TO ALLOW FOR ANYTHING MORE THAN LOW END POPS OVER
CHARLESTON COUNTY CLOSE TO DAYBREAK. UPSTREAM IT APPEARS THAT THE
BEST FORCING WILL STAY TO THE WEST...SO LESS THAN 14 POPS HAVE BEEN
FORECAST ELSEWHERE.
WHILE CONDITIONS ARE NOT AS FAVORABLE FOR FOG DEVELOPMENT AS LAST
NIGHT /IE. TOO MUCH WIND IN THE BOUNDARY LAYER UNTIL LATE AND
MUCH LESS RAINFALL/...WE HAVE OPTED TO ADD PATCHY FOG TO OUR NW
TIER WHERE THEY HAVE A BETTER CHANCE OF ACHIEVING THEIR CROSS-OVER
TEMPS AND FOG STABILITY INDICES ARE IN THE LOWER 20S.
THE MIXING IN THE BOUNDARY LAYER AND AN INCREASE IN CLOUD COVER
WILL LIMIT TEMPS TO ONLY THE MID AND UPPER 60S INLAND FROM THE
SLIGHTLY WARMER BEACHES.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
WHILE WE HAVE MAINTAINED PREVAILING VFR THROUGH 00Z FRIDAY...THERE
IS THE RISK OF MVFR CONDITIONS IN LIGHT FOG/STRATUS A FEW HOURS
EITHER SIDE OF DAYBREAK...AND ALSO MARGINAL MVFR CONDITIONS IN
ISOLATED TO SCATTERED SHRA/TSRA WITH A PRE-FRONTAL TROUGH IN THE
LATE MORNING THROUGH MID AFTERNOON. IF THE TROUGH IS QUICKER THAN
ANTICIPATED THERE COULD BE SOME GUSTY WINDS LATE IN THE TAF CYCLE.
EXTENDED AVIATION...VFR. WINDS COULD GET A BIT GUSTY FRIDAY AFTERNOON
BEHIND THE SECONDARY FRONT.
&&
.MARINE...
TONIGHT...THE SUB TROPICAL RIDGE IN THE ATLANTIC CENTERED OUT NEAR
32N AND 60W WILL START TO RELAX ITS GRIP ACROSS THE COASTAL WATERS
LATE...AS IT STARTS TO GIVE WAY TO AN UPSTREAM PRE-FRONTAL TROUGH.
THE PRESSURE GRADIENT WILL TEMPORARILY TIGHTEN A BIT BETWEEN THESE
TWO FEATURES...ALLOWING FOR SE AND SOUTH WINDS UP TO 15 KT THROUGH
ABOUT 06-08Z...BEFORE DROPPING OFF TO 10 OR LESS LATE. SEAS WON/T
CHANGE MUCH...AVERAGING 2-4 FT AND HIGHEST ACROSS THE OUTER GA
WATERS. WE/LL NEED TO MONITOR FOR SOME GUSTY SHOWERS/T-STORMS
OVERNIGHT AS LOW LEVEL CONVERGENCE INCREASES.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCHS 222334
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
734 PM EDT WED MAY 22 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL THROUGH THURSDAY. A COLD
FRONT WILL MOVE ACROSS THE AREA THURSDAY NIGHT...WITH HIGH
PRESSURE BUILDING OVER THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
QUITE A CHANGE IN THE PATTERN SINCE YESTERDAY...WITH MUCH OF THE
AREA VOID OF ANY CONVECTION EARLIER TODAY. WE/RE FINISHED FOR THE
EVENING FOR ANY SHOWERS OR T-STORMS IN THE LOCAL ZONES...WITH THE
SEA BREEZE HAVING CLEARED OUR NW TIER. IN ITS WAKE A STABILIZED
ENVIRONMENT HAS ENSUED AND WILL PERSIST.
FOR TONIGHT... THERE IS SOME CHANGES THAT WILL TAKE PLACE IN THE
LARGER SCALE,,,AS THE FIRST SHORT WAVE OFF THE EASTERN FLORIDA
COAST TO GET LIFTED NE AS THE NEXT LONG WAVE TROUGH IN THE
MISSISSIPPI VALLEY SHIFTS EAST. AS THIS TRANSPIRES...IT FORCES
THE LAST GRIPS OF THE ATLANTIC RIDGE TO PULL OFFSHORE AFTER
MIDNIGHT...AS A PRE-FRONTAL TROUGH IN EASTERN ALABAMA AND WESTERN
GEORGIA APPROACHES LATE. THE FORECAST AREA WILL THEN LIE
SANDWICHED BETWEEN THE FIRST SHORT WAVE IN THE NEARBY ATLANTIC AND
THE SECOND IMPULSE AND ITS REFLECTION AT THAT SURFACE. WHILE THERE
IS SOME INCREASE IN LOW LEVEL CONVERGENCE TO THE EAST...THE
SYNOPTIC FLOW MAY VEER TOO FAR TO THE SW TO ALLOW FOR ANYTHING
MORE THAN LOW END POPS OVER CHARLESTON COUNTY CLOSE TO DAYBREAK.
UPSTREAM IT APPEARS THAT THE BEST FORCING WILL STAY TO THE
WEST...SO LESS THAN 14 POPS HAVE BEEN FORECAST ELSEWHERE.
WHILE CONDITIONS ARE NOT AS FAVORABLE FOR FOG DEVELOPMENT AS LAST
NIGHT /IE. TOO MUCH WIND IN THE BOUNDARY LAYER UNTIL LATE AND
MUCH LESS RAINFALL/...WE HAVE OPTED TO ADD PATCHY FOG TO OUR NW
TIER WHERE THEY HAVE A BETTER CHANCE OF ACHIEVING THEIR CROSS-OVER
TEMPS AND FOG STABILITY INDICES ARE IN THE LOWER 20S.
THE MIXING IN THE BOUNDARY LAYER AND AN INCREASE IN CLOUD COVER
WILL LIMIT TEMPS TO ONLY THE MID AND UPPER 60S INLAND FROM THE
SLIGHTLY WARMER BEACHES.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A SURFACE PRESSURE TROF WILL MOVE INTO THE CWA ON THURSDAY...WITH
MOIST SOUTHERLY WINDS AHEAD OF IT AND SOMEWHAT DRIER WESTERLY WINDS
BEHIND IT. THE TROF SHOULD BE ROUGHLY ALONG INTERSTATE 95 BY EARLY
AFTERNOON...AND AREAS ALONG AND EAST OF THE BOUNDARY WILL HAVE A
CHANCE OF SHOWERS AND THUNDERSTORMS AS DAYTIME HEATING CREATES SOME
SURFACE INSTABILITY AND CONVERGENCE. FURTHER WEST...ESPECIALLY OVER
OUR INTERIOR GEORGIA COUNTIES...THE ATMOSPHERE WILL BE DRIER AND
MORE STABLE...SO THERE WILL ONLY BE A SLIGHT CHANCE OF SHOWERS.
SKIES SHOULD AVERAGE OUT PARTLY CLOUDY...ALTHOUGH THERE WILL BE A
PERIOD OF MOSTLY CLOUDY SKIES TO THE EAST OF THE BOUNDARY DURING A
PORTION OF THE AFTERNOON.
THURSDAY NIGHT...THE INITIAL COOL FRONT PUSHES THROUGH THE
AREA...MOVING THE CHANCES FOR RAIN MOSTLY OFFSHORE...ALTHOUGH I
CANNOT RULE OUT A SLIGHT CHANCE OVER THE TRI COUNTY AREA AS THERE
MAY BE ENOUGH REMNANT MOISTURE WITH THE FRONT TO PROMOTE SOME
SHOWERS.
FRIDAY...THE WINDS WILL BE NORTHWEST BEHIND THE FRONT IN THE
MORNING...PROMOTING SOME DOWNSLOPE LOW LEVEL FLOW AND HEATING.
HOWEVER...DRIER AIR MOVING IN SHOULD PREVENT ANY RAIN...OR MUCH IN
THE WAY OF CLOUDS FOR THAT MATTER. A SECONDARY COLD FRONT WILL MOVE
THROUGH LATER IN THE DAY...CAUSING THE WINDS TO VEER TO NORTH AND
INCREASE AS COLD ADVECTION PICKS UP. FRIDAY NIGHT WILL BE MUCH
COOLER THAN THE PREVIOUS FEW.
SATURDAY...TEMPS WILL BEGIN WELL BELOW NORMAL AS MODIFIED AIR POURS
IN TO THE AREA...BUT THIS TIME OF YEAR THAT MEANS TEMPS MAINLY IN
THE 50S. PLENTY OF SUNSHINE WILL ALLOW AFTERNOON MAX TEMPS TO REACH
TO 80 OR ABOVE...BUT DEWPOINTS WILL DROP INTO THE 40S AWAY FROM THE
COAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THROUGH THE LONG
TERM PERIOD. THE MID AND UPPER LEVEL PATTERN WILL FEATURE A NEARLY
ZONAL FLOW OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK...WITH A RIDGE THEN BUILDING TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...HIGH PRESSURE WILL PASS NORTH OF THE AREA LATE IN THE
WEEKEND...THEN SETTLE OVER THE WESTERN ATLANTIC THROUGH THE MIDDLE
OF NEXT WEEK.
RAIN-FREE CONDITIONS ARE EXPECTED TO PERSIST INTO EARLY NEXT
WEEK...THEN INCREASING MOISTURE COULD ALLOW FOR SOME MAINLY DIURNAL
ISOLATED CONVECTION ALONG AND AHEAD OF THE SEA BREEZE TUESDAY AND
WEDNESDAY. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL SUNDAY...THEN
RETURN TO NEAR OR SLIGHTLY ABOVE NORMAL NEXT WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
WHILE WE HAVE MAINTAINED PREVAILING VFR THROUGH 00Z FRIDAY...THERE
IS THE RISK OF MVFR CONDITIONS IN LIGHT FOG/STRATUS A FEW HOURS
EITHER SIDE OF DAYBREAK...AND ALSO MARGINAL MVFR CONDITIONS IN
ISOLATED TO SCATTERED SHRA/TSRA WITH A PRE-FRONTAL TROUGH IN THE
LATE MORNING THROUGH MID AFTERNOON. IF THE TROUGH IS QUICKER THAN
ANTICIPATED THERE COULD BE SOME GUSTY WINDS LATE IN THE TAF CYCLE.
EXTENDED AVIATION...VFR. WINDS COULD GET A BIT GUSTY FRIDAY AFTERNOON
BEHIND THE SECONDARY FRONT.
&&
.MARINE...
TONIGHT...THE SUB TROPICAL RIDGE IN THE ATLANTIC CENTERED OUT NEAR
32N AND 60W WILL START TO RELAX ITS GRIP ACROSS THE COASTAL WATERS
LATE...AS IT STARTS TO GIVE WAY TO AN UPSTREAM PRE-FRONTAL TROUGH.
THE PRESSURE GRADIENT WILL TEMPORARILY TIGHTEN A BIT BETWEEN THESE
TWO FEATURES...ALLOWING FOR SE AND SOUTH WINDS UP TO 15 KT THROUGH
ABOUT 06-08Z...BEFORE DROPPING OFF TO 10 OR LESS LATE. SEAS WON/T
CHANGE MUCH...AVERAGING 2-4 FT AND HIGHEST ACROSS THE OUTER GA
WATERS. WE/LL NEED TO MONITOR FOR SOME GUSTY SHOWERS/T-STORMS
OVERNIGHT AS LOW LEVEL CONVERGENCE INCREASES.
THURSDAY THROUGH MONDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE
WITH SOUTHERLY FLOW UNTIL A COLD FRONT PUSHES OFFSHORE EARLY
FRIDAY. A NORTHERLY SURGE IS EXPECTED TO DEVELOP IN WAKE OF THE
FRONT FRIDAY NIGHT INTO EARLY SATURDAY AND COULD RESULT IN SMALL
CRAFT ADVISORY CONDITIONS. CONDITIONS WILL THEN IMPROVE LATER IN
THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS/SEAS EXPECTED TO
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.TIDES/COASTAL FLOODING...
HIGH ASTRONOMICAL TIDES AND FAVORABLE NORTH/NORTHEAST WINDS COULD
LEAD TO MINOR SALTWATER INUNDATION NEAR THE COAST DURING THE HIGH
TIDE FRIDAY AND SATURDAY EVENING. BY THE TIME OF THE HIGH TIDE
SUNDAY EVENING AND MONDAY EVENING...WINDS WILL NOT BE AS
CONDUCIVE...YET MINOR SALTWATER FLOODING WILL STILL BE POSSIBLE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
000
FXUS62 KCAE 222323
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
723 PM EDT WED MAY 22 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL CIRCULATE A MOIST
SOUTHERLY FLOW INTO THE FORECAST AREA AHEAD OF A SLOW MOVING COLD
FRONT THROUGH THURSDAY. THE COLD FRONT WILL MOVE THROUGH THE AREA
THURSDAY NIGHT. THE DRY AIR MASS BEHIND THE FRONT WILL DOMINATE
DURING THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
LESS MOISTURE THIS AFTERNOON THAN YESTERDAY...AND RESULTING
INSTABILITY WEAKER. SHOWERS ALONG SEA BREEZE FRONT WEAKENING AS
THEY MOVE INTO MIDLANDS. STRONGER CONVECTION IN NORTH
GEORGIA/UPSTATE BUT LITTLE MOVEMENT INTO MIDLANDS. WILL CUT POPS
BACK FROM PREVIOUS FORECAST...SLIGHT CHANCE REST OF AFTERNOON AND EVENING.
SKIES WILL BECOME MOSTLY CLOUDY TONIGHT AS THE FRONT APPROACHES
FROM THE WEST WITH CHANCES OF SHOWERS INCREASING FROM WEST TO EAST
DURING THE PRE-DAWN HOURS. OVERNIGHT LOWS WILL GENERALLY BE IN THE
MID 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
MID AND UPPER LEVEL TROUGH CROSSING THE EASTERN CONUS DURING THE
SHORT TERM. THE AIR MASS WILL BE UNSTABLE WITH A PRE-FRONTAL TROUGH
OVER THE MIDLANDS. LOW LEVEL MOISTURE LINGERS WITH PRECIPITABLE
WATER RANGING FROM 1.00 T0 1.75 INCHES. THE THREAT OF CONVECTION
WILL CONTINUE WITH THE HIGHEST CHANCE ACROSS THE MIDLANDS. WILL
RANGE POPS FROM NEAR 30 PERCENT CSRA TO 60 PERCENT NORTHEAST ON
THURSDAY. ALTHOUGH THE GFS IS SLIGHTLY FASTER...MODELS INDICATE THE
COLD FRONT CROSSING THE AREA THURSDAY NIGHT WITH THE CHANCE OF
CONVECTION ENDING.
THE TEMPERATURE GUIDANCE WAS CLOSE WITH HIGHS IN THE MID/UPPER 80S
AND LOWS IN THE LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE DRY AIR MASS BEHIND THE COLD FRONT SHOULD DOMINATE DURING THE
WEEKEND. THE GFS AND ECMWF INDICATED A WARM FRONT DEVELOPING
MONDAY WITH MUCH OF THE MOISTURE NORTH OF THE FORECAST AREA MONDAY
THROUGH WEDNESDAY. GFS ENSEMBLE INCREASE POPS SLIGHTLY THROUGH THE
MIDDLE OF NEXT WEEK. WILL KEEP THE FORECAST DRY GIVEN INCREASING
H500 HEIGHTS AS THE UPPER RIDGE BUILDS.
EXPECT BELOW NORMAL TEMPERATURES DURING THE WEEKEND AND NEAR NORMAL
DURING THE REST OF THE MEDIUM RANGE PERIOD.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
RADAR INDICATES CONVECTIVE ACTIVITY AT A MINIMUM ACROSS OUR FA. MOST
ACTIVITY CURRENTLY CONFINED TO THE UPSTATE SC AND N/CENT GA. HIGH
RES MODELS INDICATE ACTIVITY DEVELOPING TO OUR WEST NEAR AN UPPER
IMPULSE AND SURFACE TROUGH...WEAKENING AS IT MOVES EAST AND
APPROACHES THE FA LATE TONIGHT. GUIDANCE INDICATING CIG RESTRICTIONS
LATE TONIGHT...IN A CONTINUED MOIST SOUTHERLY LOW LEVEL FLOW. FOR
NOW...WILL INDICATE A PERIOD OF MVFR CIGS. WILL MONITOR LATEST
GUIDANCE FOR POSSIBLE ADJUSTMENT TO IFR IF NEEDED. UPPER IMPULSE
AND SURFACE TROUGH WILL MOVE THROUGH THURSDAY...POSSIBLY LEADING
TO SCT SHRA/TSRA...BUT CHANCES TOO LOW...ALONG WITH SOME TIMING
QUESTIONS...TO INCLUDE MENTION IN THE TAF AT THIS TIME.
EXTENDED AVIATION OUTLOOK...DRIER AIR MOVING IN BEHIND A FRONT WILL
PRECLUDE ANY IMPACTS TO AVIATION...OTHER THAN BREEZY CONDITIONS
POSSIBLE FRI/FRI NT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
| 
